Japan ambassador says TPP a 'game changer'

Japan's ambassador to Australia has high hopes the soon-to-be finalised Pacific trade pact will be a game changer.

Final negotiations on the Trans-Pacific Partnership deal start in Hawaii on Tuesday.

The deal, worth more than $200 billion, will involve 12 countries including Australia, the US, Canada and Japan.

Ambassador Sumio Kusaka believes the peace and prosperity of the Asia Pacific region would be further advanced by trade liberalisation and new rules.

"I hope it will become a game changer," he told reporters at the National Press Club in Canberra on Tuesday.

Trade Minister Andrew Robb has defended the secrecy of the negotiations.