The ambitious TPP deal is now believed to have two main blocks stopping it from being finalised - dairy and medicine.

Trade negotiators from Pacific Rim nations have gathered in Hawaii to try and get the deal signed off.

Reuters reports both the U.S. and Japan want long copyright periods for drugs, and as the two biggest economies in the talks, hold a lot of sway.

Both Mexico and Canada aren't keen on opening up their protected local dairy industries to competition from New Zealand products.

Dairy access has seen PM John Key working the phones.

"I'm in the process of making phone calls to leaders and others to encourage them to see it our way - let's see how it goes."

He has also been castigated Labour for criticising the Trans Pacific Partnership Agreement.

Mr Key says Labour's attacks on the agreement are pure politicking.

He argued "this is a chance to have a free trade agreement with the USA and Japan."

Earlier this morning there was a chorus of opposition to the TPPA after the government conceded the trade deal could see medicines become more expensive.

Head of the Association of Salaried Medical Specialists Ian Powell said under the agreement overseas pharmaceutical companies can intervene in Pharmac's decision making.

"So Pharmac will actually be negotiating with one hand behind it's back, and the other hand in a sling."

Labour leader Andrew Little said if patent rights to drug companies are extended, it will make medicinal drugs more expensive.

"It is going to add cost to Pharmac and the New Zealand taxpayer, that is unavoidable."