Former state Liberal leader John Brogden and former Australian Rugby League boss John Quayle – acting as independent brokers for the NSW government – are locked in high-stakes negotiations with Stadium Australia Group managing director Daryl Kerry and Tony Shepherd, chairman of the Sydney Cricket and Sports Ground Trust.

They are battling over a state government allocation of $600 million designated for sports stadia development, as outlined in the State Infrastructure Strategy Update published by Infrastructure NSW late last year.

There is no official date for the review to be completed but it is understood the parties and the government want an announcement before the NSW election on March 28.

The funding decision will have an enormous bearing on the way Sydneysiders and the city's visitors attend and view sport.

Such is the sensitivity of the negotiations, no one closely involved, including NSW Minister for Sport Stuart Ayres, would comment on the record. But underneath background briefings was a sense that the discussions were not only a critical point in the history of the city's sporting infrastructure, but a focal point for years of pent-up bitterness between the operators of Sydney's two major sporting venues.

In a nutshell, the SCG Trust's dream outcome is that Allianz Stadium receive an overhaul or be entirely rebuilt into a 60,000-plus seat stadium and surrounds, providing Sydney with the modern rectangular-shaped venue most agree it needs.

They claim there is a global trend towards building football grounds with a capacity of between 65,000 and 70,000, and cite as an example the home of the recent Super Bowl in the US, the $US455 million ($585 million) University of Phoenix Stadium – with a retractable roof and moveable stands – which opened in 2006.

Such a development at Allianz Stadium would complement last year's opening of a new $197.5 million northern stand at the adjacent SCG, which cost the NSW government $97.5 million, and the federal government and SCG Trust $50 million each. At the least, the trust is hoping for the funds to overhaul Allianz Stadium, Sydney's premier rectangular field since it was opened in 1988, including possibly an underground carpark.

If Stadium Australia Group gets its way, the privately owned ANZ Stadium would receive $250 million from the allocation, understood to be the first time it has received public money since the stadium was built. The grant, added to $100 million of the owner consortium's funds, would pay to build a retractable roof and make the northern and southern stands mobile, like the eastern and western stands, creating a rectangular-shaped arena. It may also build a new retail precinct in the surrounds.

It might seem a straightforward decision. However, when dealing with such major infrastructure, big money and big egos – the list of directors at the SCG Trust, particularly, reads like a who's who of the powerful and influential – many factors come into play and negotiations become complex. Population movements, already commissioned infrastructure projects and long-term planning are among the elements that are being factored into the decision.

Some insiders suggest there is a genuine desire among the parties to find the best solutions for Sydney's needs and ensure the city continues to attract major events, which generate tourism, investment, tax dollars and prestige.

But others describe the competition as a war. Since Stadium Australia opened in 1999, providing a competitor to the SCG and Sydney Football Stadium, most of the battles have been sharp but ultimately a positive contest to entice sporting organisations to bring their product to this place or that. The winners have been the sports, which have brokered better deals for themselves. Yet, in this stoush, there is the spectre of an end game.

The SCG Trust's wish for a rebuilt football stadium would impact heavily on what the Infrastructure Strategy calls the "optimisation of the Sydney Olympic Park precinct and Parramatta Stadium".

It could leave ANZ Stadium isolated, especially with a strong consensus – and pressure from Football Federation Australia – that Parramatta Stadium be expanded from a 20,000 seater to over 30,000 to accommodate the Western Sydney Wanderers. Further adding pressure and complexity, also in the  Strategy Update is a recommendation "the government commence long-term planning for building an outer Western Sydney stadium".

The most extreme suggestion has been for ANZ Stadium to be razed and the land sold to build apartments. However this is unlikely to happen, as Premier Mike Baird, whose father Bruce Baird was Minister for Sydney's Olympic bid in the early 1990s, and Opposition Leader Luke Foley have reportedly refused to entertain the idea.

"I couldn't look Cathy Freeman in the eye," Foley was quoting as saying recently, referring to the Olympic stadium's historical significance.

Financially, too, doing away with ANZ Stadium appears fraught. It would mean breaking the government's contract with owners Stadium Australia Group, which runs till 2031 and which the consortium is understood to be considering extending in return for government assistance. Part of that contract is for Allianz Stadium's capacity to stay below 48,000. The amount of compensation the government might have to pay to break the contract is being discussed in the negotiations.

It may seem that ANZ Stadium's relevance is fading, with the Sydney Swans and NSW Waratahs ending their regular season association with the ground. The Swans will play exclusively at the SCG from 2017, the Waratahs at Allianz Stadium from 2016. However, the impact of these decisions might not be as severe as they seem.

Certainly, in a competition where the capital is, essentially, sporting events, the SCG and Allianz Stadium are winning. But, financially, the departure of the Waratahs and Swans is not a big hit, as volume is not as important as quality.

The big money spinners for ANZ Stadium are the rugby league games, such as State of Origin and finals, the rugby Tests including the Bledisloe Cup, and infrequent blockbusters, such as the recent Asian Cup final. Those events, added to the deals with NRL clubs South Sydney, Canterbury, the Tigers and Dragons are adequate to sell memberships, sponsorships, advertising and naming rights which, added to other revenues such as food and beverage – which is owned by the stadium – generate enough profit to cover the stadium's estimated $150 million debt.

"It's a good sustainable business, despite what the Trust people will tell you," one former board member said.

The most likely resolution to the negotiations is that both parties' needs will be met to some degree. The Infrastructure Strategy Update recommended the reconfiguration of ANZ Stadium into a rectangle. It spoke of the need to redevelop Parramatta Stadium and acknowledged the need to renovate Allianz Stadium.

The controversial WestConnex Motorway should better service Parramatta and ANZ Stadiums, while the South-East Light Rail will service the Moore Park precinct. Government money has recently gone into both precincts, building the recently opened $35 million Netball Central and AFL training and administrative facilities at Sydney Olympic Park and the $25 million bridge over Anzac Parade, linking pedestrians from Central Station with the SCG and Allianz Stadium. Both precincts should have a bright future but are in need of a clean-up.

"Each of Greater Sydney's Tier 1 stadia," the Infrastructure Update said, "requires substantial investment not only in the stadium itself, but also in the surrounding food, entertainment and transport hubs to bring the stadium offering up to the standard of comparable venues interstate, particularly in Melbourne.

"Making these investments will ensure that Sydney and NSW continue to offer ...  facilities that will help to attract visitors, new residents and investors to NSW."