Reportedly taken aback at the advanced stage of the controversial plan, McLachlan is understood to have raised a number of reservations over the proposal in a heated conversation with AFL Coaches Association chief Mark Brayshaw.

Not only have senior coaches Mick Malthouse and Phil Walsh expressed major issues with the plan, several clubs have communicated their displeasure to head office at the precedent being set by the revamped coaches' body selling off a portion of potential AFL broadcast revenue.

Collingwood has told the coaches' association it will not allow Nathan Buckley to be miked up in the coaches' box during an AFL game this season – also part of the AFLCA proposed deal with Fox.

Fairfax Media understands Buckley is one of several coaches who have refused to have their instructions recorded during games – a refusal  Brayshaw has accepted.

Collingwood president Eddie McGuire said: "There's enough fragmentation of the footy income without the coaches' union jumping in and getting involved.

"I wouldn't have thought at Collingwood we would be selling our intellectual property to the coaches' association."

Those reservations have prompted Brayshaw to write to all 18 clubs seeking their support for the Fox Footy deal. In a letter obtained on Tuesday by Fairfax Media, Brayshaw outlined the coaches' desire to gain independence from the AFL, stating that more than two-thirds of the AFLCA's income stream came from league headquarters.

Brayshaw said the reliance on AFL income was "unhealthy".

He wrote: "All our attempts to generate additional sponsorship revenue are undertaken on the following bases:

■ Partner with the AFL's major sponsors, wherever possible, so as to assist them leverage and optimise their investment in the AFL.

■ Avoid ambushing AFL/club major sponsors.

■ Try not to place any extra burden on a coach, but if this is unavoidable, offer to pay the coach an appropriate appearance fee."

While talks between Fox Footy and the AFL coaches began last year, the AFL is understood to have become aware of the negotiations only over the past 10 days, which prompted a meeting with league executive Simon Lethlean, Brayshaw and Fox Footy boss Ben Buckley last Thursday.

The AFL and its clubs have raised issues with the ramifications for the Seven Network, the selling of broadcast property potentially part of the next broadcast agreement and the concern over the image of the game should coaches placed together turn on each other after a controversial incident.

Conversely there is a view that such press conferences could generally prove bland with neither coach prepared to open up to the media.

Clubs also raised concerns that the setting of such a precedent could see the AFL Players Association follow suit in attempting to sell off their clubs' intellectual property.

Brayshaw's letter assured the clubs that all media would be invited to attend the joint press conferences and Channel Seven, "who rarely if ever broadcast the post-match press conferences live, will have access to the joint press conferences, for use in their news and TV programs".

Brayshaw stressed the deal would go ahead only with AFL approval.