In the face of mounting criticism, Prime Minister John Key has indicated that there is room to change the Auckland Super City set-up, but the controversial Council Controlled Organisation structure will be pushed into law.

His comments come as criticism of the role of CCOs continues to build, with Local Government NZ president Lawrence Yule weighing in yesterday.

In a letter to 85 mayors, Mr Yule said the Government-appointed CCOs would have control of an unprecedented level of Auckland infrastructure.

"Seventy-five per cent of Auckland's assets are going to be handled and organised by these CCOs and our particular concern is the new powers given to the Auckland City mayor will be somewhat neutered by this type of approach, which means he or she has control over that 25 per cent that's left over," Mr Yule told Radio NZ's Morning Report yesterday.

"CCOs are used by councils around New Zealand but not nearly to this degree. In the normal course of events, the new council would determine what is and what is not in these CCOs."

Basic infrastructure was being transferred in a manner "which we haven't seen in New Zealand before".

"This is a change and you need to be aware that there is potential for a loss of democracy in this process."

A growing list of opponents against the current bill and role of CCOs includes John Banks and Len Brown, Auckland Chamber of Commerce chief executive Michael Barnett, and community leaders.

Mr Key yesterday reiterated his belief in the concept of CCOs being at arm's length from councils to be more efficient.

But he conceded the select committee might make slight changes.

"We like the structure and it's important to recognise that CCOs have been in operation across Auckland for a long period of time. That doesn't mean we won't take soundings.

"No doubt the select committee will come up with some recommendations, but the core basis of the CCO operating in large areas like the Transport Agency, the waterfront and the like is going to be in place."

Labour MP Phil Twyford, an opponent of the bill and member of the select committee considering it, expected the Government to "offer the public a bone".

"But any minor tweaks to try and buy off public concern about CCOs ... if they did that they would be underestimating the depth of public feeling."

Possible changes included having the Transport CCO hold open meetings and make public their minutes and agendas.

Another possibility was to make the wording stronger around the link between CCOs and the Auckland Council, from "may require" to "must require ... a CCO to include in its statement of intent" a plan for contributing to the new council's objectives.

The new council could also require the Transport CCO to adopt a plan covering at least 10 years to "give effect to the council's strategy, plans, and priorities".

Mr Twyford had a heated exchange with Local Government Minister Rodney Hide in Parliament yesterday, in which he stated the level of opposition to the bill.

As Mr Hide responded, Mr Twyford shouted, "Is that the best you can do?", to which other members across the House retorted, "Take your pills, Phil".

The Green Party said individual councils decided whether to have CCOs, and that should apply to the Super City.

Most Auckland-based National MPs declined to comment.

Hunua MP Paul Hutchison said although local feedback had been mixed, he supported the current bill, as did Waitakere MP Paula Bennett.

Northcote MP Jonathan Coleman said feedback from his electorate had broadly been in support of the bill.