The future of TPP hangs in the balance as the world waits for the US Congress to pass the mega trade deal.

Presidential candidates Hillary Clinton and Donald Trump oppose the 12-nation TPP.

New Zealand's Special Agricultural Trade envoy Mike Peterson said the business interests in the US are pushing hard to get the TPP across the line.

"Now the business interests are seeing the chances of a trade agreement with Europe slipping away, and they know that they need to get more integrated with the rest of the world, and TPP's the opportunity to do that in what is the fastest growing region on Earth."

Mr Peterson said the odds of the US Congress passing the trade deal are about 50/50.

"The political process in the United States is incredibly complicated but we are seeing a real push from the Obama administration and his trade officials to really try and get TPP across the line."