A Labour MP says he's identified the Mossack Fonseca client who was cleared to buy land in New Zealand.
The Panama-based company has been at the centre of a global uproar over secretive foreign trusts since millions of its documents were leaked.
David Cunliffe says approval was granted in 2014 for the sale of Onetai Station in Taranaki to Ceol and Muir, a Mossack Fonseca client that's also based in Panama.
Ceol and Muir announced the purchase of the 1320ha station in April 2014 and it was reported by New Zealand media.
The company described itself as an Argentine/Italian consortium and said it planned to increase sheep and beef production on the station.
The purchase was handled by New Zealand law firm Kensington Swan, which said it had been looking for a suitable property on behalf of Ceol and Muir for some time.
After Ceol and Muir bought the station, which is near Awakino, local beef farmers were taken on as advisers and some are reported to be directors of Onetai Farms Ltd.
The Government said in April this year it knew about the transaction and had asked the Overseas Investment Office to review it to make sure everything was above board.
"The Government’s contention that only one application is caught up with Mossack Fonseca needs further scrutiny, especially when the OIO admits it has taken a 'lighter touch' in rejecting applications. The OIO should be our safeguard, but with only one application declined since 2011, questions should be asked about the effectiveness of its oversight."
Mr Cunliffe says he isn't suggesting anything was wrong.
"I'm not calling into question the reputation of individuals," he told RNZ.
"But we do not know, and we must be told, exactly what good character tests were applied, and to whom, when approval was granted."
Foreign trusts, which Mossack Fonseca specialises in setting up, are legal but they can be used to hide wealth and launder money.