AUCKLAND – U.S.-led talks in New Zealand on a free trade deal for the Asia-Pacific region have made some progress but have a long way to go to reach a pact to dismantle entrenched trade barriers by the end of next year, the negotiators said on Wednesday.

Several hundred officials from 11 countries have spent more than a week in Auckland for the 15th set of negotiations on the Trans Pacific Partnership (TPP), which began in March 2010.

New Zealand's chief delegate said the talks had brought new TPP members, Canada and Mexico, into the process and made progress on the language and mechanisms of any deal, as well as clearly identified what needs to be done on the difficult issues such as intellectual property, environment and investment.

"There is considerable amount of work to do," David Walker told a media briefing, adding there was a common desire among the 11 nations to reach a deal next year.

"On the various market access negotiations, discussions continue as we move towards construction of an overall package, which meet the ambitions set out by leaders and ministers and is acceptable to all," he said.

There is no formal deadline for an agreement, but October next year is being targeted to coincide with the annual summit of the Asia Pacific Economic Cooperation (APEC). The next round of talks will be held in early March in Singapore.

The major roadblocks to a final deal were not detailed, but the sensitive issue of pharmaceuticals, where the United States wants to see greater patent protection for its drug companies was not discussed.

Critics said the TPP was still aimed at benefiting large U.S. corporations.

"The proposals give greater power to large corporations and fleet-footed investors who would have little interest in creating good jobs and improving social conditions," said Bill Rosenberg of the NZ Council of Trade Unions.

Other issues the TPP is struggling with include a common dispute resolution process, which could see government measures challenged by private companies, state procurement policies, and greater intellectual property protection.

Australia reaffirmed it would not sign any deal that allowed foreign companies to challenge its laws, while Malaysia said it had problems with suggestions covering government purchasing.

Farmer groups in New Zealand, Australia, and Canada have called for the elimination of trade barriers on agricultural products.

The original four nation TPP of New Zealand, Chile, Singapore, and Brunei, now includes the United States, Australia, Malaysia, Vietnam, Peru, and most recently Canada and Mexico. Thailand and Japan are looking at joining.

Collectively the TPP countries represent 650 million people in some of the fastest growing economies in the region with a total gross domestic product of around US$21 trillion.

Last month, talks were launched for a new 16 nation free trade agreement – as the Regional Comprehensive Economic Partnership (RCEP) – grouping the 10-nation Association of South East Asian Nations (ASEAN) along with Australia, China, India, Japan, Korea, and New Zealand.

Separately, the U.S. Trade Representative Ron Kirk acknowledged the TPP talks had a long way to go before reaching a deal, although he was confident it could be done next year.

"I think we can get it closed," he said at a policy think tank gathering in Washington.