A Wellington property developer has won an appeal against a ruling preventing him from demolishing a heritage building in central Wellington.

In the High Court, Justice David Collins said the Environment Court made two errors of law in turning down developer Mark Dunajtschik’s application to demolish the Harcourts Building on Wellington’s Lambton Quay.

The building only meets 17 per cent of the building code and is in need of earthquake strengthening.

The Environment Court erred when it said alternatives to demolition were to be exhaustively and convincingly excluded, as that test didn’t meet the Resource Management Act or district plan, Justice Collins said.

The court also did not fully weigh the risk to public safety in the event of a moderate earthquake.

Justice Collins allowed Mr Dunajtschik’s appeal for a rehearing.

He said the court should only consider demolition if it is convinced there is no reasonable alternative.

It must also consider the risk to public safety and surrounding properties if the Harcourts Building remains where it is.

The 86-year-old building is valued at $10 million and has 16 people working in it with six of its eight floors vacated, compared to 400 people when it was fully tenanted.

Before the Canterbury quakes it was valued at $19.5 million.

Mr Dunajtschik has said the building will crumble and the council wouldn’t take the it off his hands when he offered to sell it for $1.