SkyCity convention centre design ready next month

An artist's impression of the Sky City National Convention Centre.

A revised design for the controversial SkyCity convention centre will be completed by the end of next month.

"The Crown and SkyCity have been making good progress discussing a revised preliminary design," Economic Development Minister Steven Joyce said.

"This is a large and complex project. There are some matters that need resolution before the revised proposal is submitted for approval by Ministers and the SkyCity board."

The casino operator had submitted a design in October last year, but when total construction costs exceeded the agreed $402 budget it pushed for a taxpayer contribution.

Prime Minister John Key initially suggested that could happen to avoid the construction of a possible "eyesore", but the Government later agreed the initial budget of $402 million should be stuck to.

Opponents of the deal will be keen to see what changes have been made to concept drawings.

The casino has indicated it will end up spending more than the agreed budget.

SkyCity and the Government agreed a deal in July 2013 for the casino operator to spend $402 million to build and operate the New Zealand International Convention Centre in exchange for legislation allowing the company to operate additional gambling tables and machines and extending its gambling licence to 2040.