Key Points:

New Zealand and Australia have signed a free trade agreement (FTA) with 10 Asian countries representing a market of more than 500 million people.

Trade Minister Tim Groser, who tonight signed the agreement in Hua Hin, Thailand, said that over time 99 per cent of New Zealand's trade in key Asian markets would be duty free.

The FTA is with members of the Association of South East Asian Nations (Asean) - Indonesia, Malaysia, Philippines, Singapore, Thailand, Brunei, Vietnam, Laos, Myanmar and Cambodia.

Mr Groser said he hoped it would come into force as early as July, after parliamentary approval.

"Significant benefits for New Zealand exporters have been achieved, including the phased elimination of trade barriers, greater certainty and transparency, and reductions in associated transaction costs," he said.

"Asean is New Zealand's third-largest export market, growing 121 per cent since 2000 and worth $4.6 billion in 2008."

Under the agreement, tariffs will be eliminated in 2010 on New Zealand exports worth $429 million a year, including in some markets butter, milk powder, wool, kiwifruit, apples and some manufactured products.

Tariffs on a further $435m of exports to Indonesia, Malaysia, Vietnam and Philippines will be eliminated between 2011 and 2020.

Within 12 years 99 per cent of tariffs will have been eliminated in the key markets of Indonesia, Malaysia, Philippines and Vietnam.

When the FTA is fully implemented it will mean annual duty savings of about $50m.

Asean's side of the agreement means that by 2010, 85 per cent of their exports will enter New Zealand duty free.

All New Zealand tariffs on Asean goods will be phased out by 2020.

Mr Groser said the FTA would send the message that New Zealand, Australia and the Asean countries believed that continued regional economic integration, not protectionism, was the best way to get through the most serious international economic crisis since the Great Depression.

Negotiations for the FTA, known as the Asean-Australia-New Zealand Free Trade Area, took place during the term of the previous government.

Mr Groser was accompanied at the signing ceremony by Labour's trade spokeswoman, Maryan Street.