The change of prime minister across the Tasman could speed up the sign off of the controversial Trans-Pacific Partnership.

Malcolm Turnbull has replaced Tony Abbott as Liberal leader, becoming the country's forth prime minister in as many years.

Trade minister Groser said Mr Turnbull has made signing off the Asian and North American free trade agreement a priority.

He said Mr Turnbull's appointment is a positive sign for the agreement, which has faced some significant setbacks in recent months.

Meanwhile, business leaders are being asked to help get the public on-side about the controversial and highly secretive Trans-Pacific Partnership.

Signing off the Asian and North American trade agreement is central to the Government's ambitious free trade agenda.

Mr Groser said business and trade leaders need to be knowledge leaders, and speak in support of the deal.

He said New Zealand's trade with countries with which we don't have free trade agreements continues to decline every year.

By comparison, our trade with other countries continues to increase.