Goodman Property Trust will sell three of its Auckland offices for $NZ206 million ($A196.98 million) to reduce debt.

New Zealand's second-biggest listed property investor will sell its two Millennium office estates on Great South Road in Greenlane and the adjoining Yellow HQ building to local investor Oyster Management.

Goodman has been overhauling its portfolio, selling more than $NZ300m of assets and signalling more than $NZ350m of new development projects over the past three years, which it says will deliver the biggest return to unitholders.

In a statement to the NZX, John Dakin, the chief executive of Goodman NZ which manages the trust, said the sale was a continuation of its investment strategy and would reduce its loan-to-value ratio by about 5 per cent.

As of March 31 this year, Goodman's look through loan-to-value ratio, which incorporates its 51 per cent stake in Wynyard Precinct Holdings, was 33.9 per cent.

"With asset disposals funding the trust's award-winning development program we're rebalancing the portfolio with greater investment in the Auckland industrial sector," Mr Dakin said.

The sale is conditional on Oyster Management's due diligence and is due to settle on December 15.