On Tuesday, opposition leader Peter Cumming called on the council to explain why Brisbane company Sniip was handed the potentially lucrative business of supplying a new way to pay rates bill without tenders being called.

Sniip approached the council in March 2015 to put forward its digital payment option where customers could scan a QR code to pay their bill.

Cr Cumming said documentation, obtained by the opposition, showed senior council officers advised against adopting the app as the take-up rate of QR codes in Australia was "disappointingly low" and the project had "little value".

"The council proceeded with a trial of Sniip despite clear advice to the contrary by its chief financial officer," Cr Cumming said.

On May 26, 2015, council COO Paul Oberle sent a briefing note, sighted by Fairfax Media, to the council's then-finance chairman Julian Simmonds that said the council did not support the use of Sniip.

"[The Digital Strategy and Innovation Branch] advice is to avoid using a third party app as there is little value in inserting a third party between council and its customers that requires the customers to download an app (which council does not control), to scan a QR code that redirects them to a payment page," the briefing note said.

Despite this, a trial of the Sniip app commenced in December 2016 and has just been extended for a further 12 months.

Cr Cumming questioned if Cr Simmonds alleged relation with Sniip chief executive Damien Vasta affected the agreement being reached.

"[Mr Vasta] told the [council] officer he had a relationship with Cr Simmonds and said he would ring him to speed up the process," Cr Cumming said.

"It is not a good look.

"If Cr Simmonds had a relationship with Mr Vasta, he should have declared a conflict, not taken a hands-on role to push this through.

"Cr Simmonds must explain why he gave this potentially lucrative leg-up."

The council said there was no relationship between Cr Simmonds and Mr Vasta and finance chairman Krista Adam denied any wrongdoing in trialling Sniip.

"Sniip has been extremely well received by property owners, with more than 9,000 payments already made through this app over three rating quarters," Cr Adams said.

But, to date, the council has not paid a cent for the service.

Cr Adams said council officers had a concern about the cost of the service, so Sniip offered the council a free trial.

"Further analysis revealed that Sniip payments would be less expensive to administer than some other payment methods."

The free trial has already run over three financial quarters and has been extended for another 12 months, but it is unclear how much it would cost the council to continue with the service after the trial.

Mr Vasta denied all allegations challenging the validity of the company's agreement with the council.

"I completely deny any suggestion that Sniip received favourable treatment," Mr Vasta said.

"Sniip went through correct and thorough processes to be awarded the opportunity to conduct a trial with Brisbane City Council."

Mr Vasta said he had no personal relationship with Cr Simmonds and had not met him prior to perusing negotiation with the council.

"We totally reject any hint of wrongdoing in the awarding of this trial contract and feel this issue has only been raised for political point scoring,'' he said.

"What a shame that a local company trying to offer genuine innovation to ratepayers is treated this way."

When Fairfax Media asked why internal council communication referenced him speaking of his "relationship" with Cr Simmonds if he, in fact, did not have one, Mr Vasta refused to comment further.

Mr Vasta also declined to comment on the value of the free services he had already provided to and would provide to the council in the future.

Sniip will continue to offer a free service to the council until October 2018.

Cr Simmonds was present in the council chamber on Tuesday, but did not address the issue.