New Zealand's government came under increasing international pressure Wednesday to release the text of the controversial 12-nation Trans Pacific Partnership (TPP) trade deal before it is signed.

Senior legislators in seven countries had signed an open letter calling for the TPP text to be released to allow effective legislative scrutiny and public debate in their countries before it was signed, said Auckland University Law Professor Jane Kelsey, who has campaigned against the secrecy of the ongoing negotiations.

The open letter followed approaches to senior politicians from Australia, Canada, Japan, Malaysia, Mexico, New Zealand and Peru, who had expressed concern about the lack of transparency in the TPP negotiations, Kelsey said in a statement.

As New Zealand was the repository of the TPP, it was effectively the secretariat, she said.

Trade Minister Tim Groser needed to take the lead when the trade ministers were meeting in Singapore from Feb. 22 to 25 and propose that they revoke the agreement of not releasing the documents.

The New Zealand government on Tuesday blocked attempts to have the full text of the TPP agreement released to Parliament before it was signed, after the main opposition Labor Party called for its release at least two weeks before it is signed.

Legislators from other countries have gone further, demanding the release of the draft texts to allow them to do their job as legislators, open the process to expert analysis and democratic debate, and remove the reliance on leaked texts, said Kelsey.

Groser told the BusinessDesk news service Wednesday that campaigners against the TPP negotiations wanted the negotiating texts made public to help ensure the process failed.

"Anything worthwhile in life, as any adult with adult experience knows, when you're trying to get people to shift positions or agree on something which they're not comfortable with, requires discretion," Groser said in the report.

Critics claim that the TPP agreement would curb national sovereignty on matters such as health and safety and environment regulations.

An academic review last week rebutted the government's claim that New Zealand would see an economic gain of 4.5 billion U.S. dollars by 2025 from the TPP as "doubtful."

The review, commissioned by the Sustainability Council of New Zealand, said the estimate from the U.S.-based Peterson Institute was calculated using methods outside established economic theory. Endi