SITE PLAN: The Lombard Lane development proposal. The complex would contain boutique shops and eateries.

A multimillion-dollar Melbourne-style mall is planned for central Wellington, with a private developer seeking ratepayer backing for the boutique shopping and eating complex.

The mall would transform the area around the old post office between Victoria St and Lombard Lane, with room for 10-15 shops and eateries in the 1068-square-metre space.

Wellington City councillors will debate today whether to pledge $150,000 of ratepayer money to investigate the project's development.

Cook Strait Properties is behind the project, and co-director Luigi Muollo said the aim was to revitalise an area of the city that was currently underused.

The earthquake-prone former New Zealand Post building on the corner of Manners Mall and Victoria St would be demolished to make way for the Jasmax architects' design.

The size of Denton Park would be doubled, creating a "vibrant" connection between Bond, Willis, Manners and Cuba streets, Muollo said.

The complex would be set back to create better sightlines for drivers along Manners Mall, and a modern pedestrian veranda. It would not exceed 7 metres in height, allowing plenty of light.

"It's solving a whole heap of issues in one go, and giving Wellington [city council] bang for their buck."

It was likely the council would need to contribute only about $350,000 of the eventual cost, Muollo said - an estimated $150,000 to upgrade Denton Park, and $250,000 to repave Lombard Lane.

If given the initial tick from the council, the next step will be resource consent. Following that, Muollo said the complex could be built in 12 months.

During a briefing at the start of Annual Plan deliberations yesterday, council urban design and heritage manager Julia Forsyth suggested councillors include $150,000 in the budget for investigations into the project, saying it would "certainly contribute to significant regeneration in this area" of the city.

Some councillors have questioned whether it is appropriate to get involved with a private developer when there is no certainty around the project.