Business leaders representing the dairy, wine and timber sectors have made a public show of support for the 15th round of Trans Pacific Partnership negotiations kicking off among 11 countries in Auckland this morning.

The Government and business backed NZ US Council, which exists to build New Zealand's relationship with the US, has published an open letter to Prime Minister John Key, signed by 50 business leaders.

NZ-US Council executive director Stephen Jacobi said the letter endorses the negotiating effort underway but recognises that it's complex, and the final result will be put forward to Parliament as part of the treaty-ratification process.

The organisation has also launched a website, www.tradeworks.org.nz, to showcase the potential benefits of TPP.

Jacobi was joined by Fonterra director Malcolm Bailey and founder of Kim Crawford Wines Erica Crawford in an address to media in Auckland today.

When questioned about why business has come forward to garner public support at this stage of the negotiations Crawford said: "I think there has been a fair bit of scaremongering and we are trying to balance the view.

"We have confidence that our negotiators have experience in free trade agreements and won't be pushed over by the big boys and won't give away the family silver."

Critics of the TPP have pointed out the deal is being done in secrecy, it could open the NZ Government to litigation from multinational companies, and compromise the Crown-owned Pharmac system.

Jacobi said all trade agreements have to be founded in good domestic policy and the TPP was no different.

"A lot has been done to give New Zealanders the impression that everything is being done in secrecy. The plan is to grow jobs."

On the question of New Zealand's chances at opening up access for dairy exports to the US market given the strong opposition from US lobbyists, Bailey said it was natural for lobbyists in the US to push back, and if it can't get a good enough deal, then there was a "walk away point" and the deal wouldn't happen.

"I want to reinforce the point that all these business have come forward to support the TPP because it's not just about our businesses but will create jobs in this country. It's far more than a free trade agreement with the US. It's expandable beyond the 11 countries."

Crawford said the deal was important to the wine industry with exports of $400 million annually.

"I see no reason for that not to double [as a result of a TPP agreement]."

A TPP deal would ensure New Zealand's export industry had an homogenous set of standards integrated across the regions rather than the current complex system.

"It will help invite investment to help forge a route to market. That is the part we don't do very well at the moment."

Pressure has ramped up on the countries to agree since US President Barack Obama named October next year as a deadline for a completed deal.

This round of TPP negotiations, held at SkyCity, are expected to finish on December 12.

- © Fairfax NZ News