EXCLUSIVE - Panama Papers NZ - Mossack Fonseca's main New Zealand agent, Roger Thompson, drafted legal documents for his foreign clients instructing them to avoid countries that have information-sharing agreements with New Zealand, the Panama Papers show.

Please note that this article has been the subject of a complaint to the Online Media Standards Authority. The findings are reported here.

When Panama Paper stories first appeared, Prime Minister John Key denied New Zealand was a tax haven, saying the country "has full disclosure of information".

"A tax haven is where you don't declare information, you can't get information, a locked box… We have information-sharing agreements or double-tax agreements with over 100 countries," he said.

Panama Papers NZ - Read our full coverage

Photo: SUPPLIED / Bentleys

However, documents show the Mossack Fonseca agent specifically advised his clients to avoid countries with information-sharing agreements with New Zealand.

The documents include a power of attorney form dated 14 March, 2014 that Mr Thompson prepared for an Ecuadorian client.

It said the client was "absolutely prohibited from managing the company in the following countries which have a DTA [double-tax agreement] signed and enforced with New Zealand."

Mr Thompson then listed "Australia, Austria, Belgium, Canada" and 34 other countries the client must avoid because they have double tax agreements with New Zealand.

The documents authorised the client to use the bank account of a foreign company or trust that has been set up without any mention of the client's name and address.

Photo: AFP / EYEPRESS NEWS / EYEPRESS

Another document prepared for an Ecuadorian investment broker in September 2014 had similar wording. It said the power of attorney could be used in the client's home country "or in any other country provided that such country does not have a double-tax agreement signed and enforced with New Zealand."

Mr Thompson also instructed his clients to avoid any countries that might subsequently enter into double-tax agreement (DTA) with New Zealand.

Massey University senior lecturer in taxation, Deborah Russell, who was shown the document, said the structures "seem to have been set up to avoid information sharing with overseas jurisdictions".

The document appeared to be making sure the information about the company stayed in New Zealand and couldn't get out to tax authorities elsewhere, she said.

Photo: RNZ / Claire Eastham-Farrelly

A complex structure of companies and trusts had been established by Mr Thompson and Mossack Fonseca for each client, with "nominee" shareholders and directors, but no mention of the real owners in Ecuador.

The power of attorney documents then gave the Ecuadorian owners use of offshore bank accounts set up in the name of the companies and trusts.

"There's double insulation going on there," Ms Russell said. "It's not just all the proxies [nominee shareholders and directors], it's making sure the [company owners] are shielded from the double-tax agreements."

In addition to double-tax agreements, New Zealand also has Tax Information Exchange Agreements with various tax haven nations, to help IRD seek information about New Zealanders using the tax havens.

There are none of these agreements with the Latin American countries where Mr Thompson and his colleagues do business.

*The investigation into New Zealand links in the Panama Papers is a journalistic collaboration by reporters from RNZ, One News and investigative journalist Nicky Hager, and with the assistance of the International Consortium of Investigative Journalists and the German newspaper Suddeutsche Zeitung.