The ASB Showgrounds wants to develop a $229 million convention and exhibition centre on mostly vacant land at Greenlane.

Showgrounds chief executive Mark Frankham said a 5500-seat centre could rise on the northern side of the site, alongside the expanded exhibition halls, on which $30 million has been spent.

The showgrounds bid was the cheapest submitted to the Government from Auckland businesses and construction was ready to start almost immediately, he said.

The Auckland City Council said the most expensive option was a $550 million national convention centre on the waterfront on a redeveloped wharf.

The showground's expanded exhibition halls have 3.5ha of indoor floor space, and Mr Frankham said that gave Greenlane the edge over other Auckland sites.

But he acknowledged all the other pitches had come from CBD locations. Conventions catering for up to about 22,000 people annually aimed to showcase the central city and waterfront.

To resolve Greenlane's accommodation problem, Mr Frankham said, a four-level 450-room $100 million hotel could be built alongside the new centre and that was part of the showground's proposal designed by architects Archimedia.

The chairman of the Auckland City Council city development committee, Aaron Bhatnagar, said Wellington, Christchurch and Queenstown might also pitch for the national convention centre.

"Greenlane most certainly has some strengths, particularly the fact that it has land available and is closer to the airport, which it believes are good selling points.

"The council wants to bring an international convention centre to Auckland but we took an agnostic view on the location."

The Government would pick the city and site, he said.

Mr Frankham wants to use land between the existing convention halls, Puriri Drive and Greenland Rd. The wooden grandstand where the showgrounds business has its offices would be demolished or moved to make way for the development, he said.

The showground proposal is one of about five from Auckland which were to go to the Ministry of Economic Development last Friday to be considered as a response to Economic Development Minister Gerry Brownlee's call for a 3500-seat to 5000-seat convention centre.

SkyCity wants to develop at 101 Hobson St opposite its casino, Ngati Whatua o Orakei Maori Trust Board on land near Vector Arena and The Edge alongside Aotea Centre. Waterfront proposals for Wynyard Point and Bledisloe Wharf might also have been submitted.

Mr Frankham said Greenlane was by far the best site because it was flat and had ample surrounding space for the huge amount of space needed when equipment was brought in to cater for big events.

A large part of the Showground's 8.2ha site was undeveloped, he said. The site is owned by the Cornwall Park Trust Board and the showground business has a lease in perpetuity, with rent reviewed five yearly.

The Contenders
Auckland's convention centre options:
* $550m on rebuilt wharf.

* $477m on land and water.

* $405m on a wharf.

* $383m at Wynyard Pt.

* $329m at Midtown, CBD

* $229m at ASB Showgrounds.

- Sources: Auckland City Council report/ASB Showgrounds' bid