The seating capacity of the planned Canterbury Multi-Use Arena has been increased to 30,000.

Christchurch city councillors voted to approve a notice of motion at a meeting on Thursday reversing the 25,000-seat option approved last month.

BESIX Watpac, the chosen contractor, provided the council with a report detailing the options for increasing the seating capacity which said an increase to 30,000 would cost an additional $50 million.

An increase to 27,500 would cost an additional $10 million.

The councillors voted 15-1 in favour of the 30,000-seat arena.

The 'Keep Canterbury Multi-Use Arena to 30,000 seats' petition was presented to the council with 24,116 signatures calling for the 30,000 seats to be retained and not downsized.

The petition, which was 479 double-sided pages, received a round of applause from those in the chambers that was packed with onlookers.

Mayor Lianne Dalziel said it was a "very powerful presentation".

General manager of Citizens and Community Mary Richardson said it was critical that contractors and staff had clear and unequivocal design direction to move to its preliminary design as soon as possible.

"Uncertainty and controversy will impact on cost, public confidence and ability to raise external funding," she said.

Controversy had surrounded the decision to reduce the seating capacity of the arena to 25,000, after the budget had already blown out by $131 million.

Councillors Sam MacDonald, Phil Mauger, Catherine Chu, James Gough, and Aaron Keown voted to keep the capacity at 30,000.

Crusaders chief executive Colin Mansbridge told Mike Hosking on Newstalk ZB it would be interesting to see what the outcome was.

"If it's 25,000, let's get on and build 25,000, if it's 30,000, that's even better. Let's get on and build 30,000," he said.

Canterbury Employers' Chamber of Commerce chief executive Leeann Watson said the overall economic impact for the city would be compromised if the seating capacity was to be reduced.

"There's no doubt about that. We know that some of the big sporting events such as All Blacks test matches will be compromised if we don't have 30,000.

"Why would we build something that is not going to enable us as a city to be competitive with other main centres around the country when we've got an opportunity to build a first-class, purpose-built facility?"