John Key's explanation of how the illegal spying on Kim Dotcom occurred is wrong in law and could not have happened the way he describes, legal experts say.
Instead, the Prime Minister's statements about the Government Communications Security Bureau raise questions about the information he relied on before making two public statements.
Opposition leader David Shearer said it appeared the error was a "smokescreen". He said the finding cast doubt on the quality of briefing the Prime Minister was receiving. "It looks more like cover-up than getting to the truth of what went on."
It comes after Mr Key conceded a loss of memory over the GCSB's involvement in the arrest of Mr Dotcom.
Mr Key has twice explained that GCSB officers accidentally spied on Mr Dotcom after becoming confused because the law changed during the time he entered the country.
Eight days ago he said: "Had he come to New Zealand at the time without changes to the other laws, particularly GCSB's law, then his activities would not have been protected."
Then last Monday he said: "... this guy has been given a visa, he has been given one under the old law and under the old law he wasn't protected and it was that change to the new act that actually caused the problems."
A review by the Herald of the legislation that governs the GCSB raised questions about the accuracy of the explanation. The Weekend Herald asked three lawyers to review the two immigration acts and the GCSB law.
University of Auckland emeritus professor of law Jim Evans, an expert in interpreting the meaning of laws, said: "It is not true that 'had he [Mr Dotcom] come to NZ at the time without changes to other laws, particularly GCSB's law, then his activities would not have been protected'.
"So long as he was granted a resident permit when he arrived, his activities would have been protected."
Professor Evans also found the law stated Mr Dotcom's clearance to travel to New Zealand would have converted to a residence-class visa under the new law - also meaning he was protected from intrusion.
Mr Dotcom's immigration file, released to the Herald through the Official Information Act, shows he travelled to New Zealand as a tourist three times between December 2008 and March 2010. Just before the latter trip, immigration experts Malcolm Pacific approached Immigration NZ to discuss applying for a business visa under the "investor" category, which exists to draw wealthy individuals and their families to settle here.
The residence visa granting permission to travel to New Zealand was granted on November 18, 2010. Under the 1987 immigration law, the "visa" gave potential residents the right to travel to the border. Once there, they were required to apply for a "permit" to enter the country.
Documents in the immigration file show Mr Dotcom landed here on December 15, 2010. In the 27 days between being approved to travel here and getting here, a new Immigration Act came into force.
It made minor changes to the GCSB law but the legal review for the Herald found it made no difference to the protections offered to Mr Dotcom under the old law. The former GCSB law said those holding "residence permits" were protected from GCSB spying.
The changes in the law meant Mr Dotcom was covered by the new law on arriving.
Under the old law he would have had to ask at the border for a residence permit, which would then have conferred protection.
The review debunks the explanation given by Mr Key on two occasions - when he apologised to Mr Dotcom a week ago and again on Monday at his post-Cabinet press conference.
A spokeswoman for Immigration New Zealand said: "Essentially, the difference between the two [laws] is that the new act uses the single term 'visa' for authority to travel to and stay in New Zealand. The term 'permit' is no longer used."
Green Party co-leader Russel Norman said the review for the Weekend Herald - if correct - meant a new legal review was needed.
He said the Prime Minister also needed to explain who he was briefed by and what questions were asked.
"It is starting to look like a legal whitewash."
Mr Key's office said there would be no comment until next week.
Neazor's law-change claims 'miss point'
The inquiry finding into the GCSB illegal spying is still accurate - but Paul Neazor's claims of a law change miss the point, say lawyers who reviewed the law.
Justice Neazor investigated the spying as the Inspector-General of Security and Intelligence.
His report referred twice to a law change, which lawyers say confused the issue. In one area, he said Dotcom was not protected from the GCSB because he held a residence-class visa issued under the old law.
He's right - because only foreigners outside New Zealand could hold a "visa" under the old law. The "visa" got travellers only to the border where they needed a "permit" to get it - and that gave protection from spying. In another section, he referred to foreigners being those who held a residence visa under the old law.
Dotcom only ever entered New Zealand under the new law.