Speaking at an open section of the corporation's board meeting yesterday, corporation general manager Craig Norman said Buildev had 60 days to complete its due diligence on the site.

"If not, the site will be going back on to the market again," Mr Norman said.

After the meeting, Buildev development manager Darren Williams said the company was "absolutely certain" the sale would proceed.

"This has been a long time in the making, it's three years since we first bid on the site and so we need to do some final measurements and inspections before we can go ahead, but there is no doubt we will be doing it," Mr Williams said.

Buildev and two other bidders were shortlisted in August 2007 and the Honeysuckle-based company was announced as preferred tenderer in December 2008.

As part of the deal, Buildev will assume responsibility for remediating the site, a cost the corporation had estimated at $24 million.

The meeting heard the Buildev plan could bring up to 3000 jobs, with 10 hectares supporting port-related industry and the remaining 52 hectares suitable for light industry, warehouses, distribution and office use.

The meeting heard that work would start in coming months on a single rail line to run across the centre of the broader 152-hectare former steelworks site.

It would run from the eastern or Selwyn Street end of the site and finish at the western or OneSteel end and help the movement of cargo.

Work was also starting this year on a sewer pump and rising main near the Selwyn Street boundary.