Bill English's role in trying to "cover up" spying on Kim Dotcom faces scrutiny after new evidence shows the internet entrepreneur was under illegal surveillance longer than previously admitted.
The Prime Minister has refused to comment citing ongoing legal action - unlike predecessor John Key, who made his initial public apology to Dotcom during a slew of High Court proceedings and went on to answer questions.
But the legal action which disclosed the extended spying also targets English specifically, saying he acted "unlawfully" when he signed a ministerial certificate intended to bury the spying operation forever.
A High Court judgment made public last week included a key detail which stated surveillance on Dotcom went on longer than previously sworn testimony from spies had admitted.
Previous sworn testimony to the High Court has seen Government Communications Security Bureau (GCSB) staff stating they spied on Dotcom until January 20 2012 - the day of the police-FBI raid which saw Dotcom and three others arrested.
But the latest High Court judgment said the spying continued until March 22 2012 and has drawn focus back to those involved at the time the GCSB first admitted illegal surveillance.
English was at the centre of it and documents filed with the High Court seeking compensation for the illegal spying include allegations English "acted unlawfully" when the spying was about to come out.
The original claim against the GCSB stated "the Honorable Bill English acted unlawfully in signing the ministerial certificate suppressing all details of the GCSB's involvement" in the police raid on Dotcom.
English came to be involved when the possibility of spying emerged in 2012 during a court hearing in the Dotcom case.
In the weeks leading up to it being made public the GCSB went to English, who was acting Prime Minister at the time because Key was out of the country, to try to have its involvement made a state secret.
English was briefed by then-GCSB director Ian Fletcher and the former acting director - and legal expert - Hugh Wolfensohn on the GCSB's assistance to police in the raid which saw Dotcom and three others arrested on copyright charges.
What English was told is not known - but he signed the only ministerial certificate known to have been issued, giving a total legal shield to anyone involved to refuse any court or other order revealing details.
The certificate stated that making public the GCSB's involvement "would likely prejudice the security of New Zealand" by undermining efforts to detect and prevent serious crime.
It also said such publicity would harm New Zealand by damaging the flow of information from overseas intelligence agencies.
When it emerged that Dotcom and two others spied on - his then-wife Mona and co-accused Bram van der Kolk - were New Zealand residents, the ministerial certificate collapsed because the GCSB had broken its own law to carry out surveillance on them.
Key then apologised - although his comments at the time don't appear to carry any specific reference to when the spying ended.
The New Zealand Herald asked English's office if he was made aware of the dates over which the surveillance took place - and whether he was told the spying went longer than the January 20 2012 date in court documents.
The spokeswoman refused to answer, saying "as the matter may be subject to further court action, it would inappropriate to comment further".
The GCSB has likewise refused to answer questions, also citing the court action. GCSB minister Chris Finlayson has claimed the same.
Dotcom said the new spying period covered when he was in Mt Eden prison awaiting bail - a period during which he has previously claimed to have been under surveillance.
"The ministerial certificate was an attempted cover-up. Bill English must have been briefed that GCSB was facing legal troubles because of unlawful conduct.
"And only after the attempted gag-order failed in the High Court did the Government admit unlawful spying with a fake narrative that it was all a big mistake, a misunderstanding of the law, an error."
Dotcom said there would be new legal action taken to try to extract details from the GCSB.
"The new revelations completely undermine the government narrative and it raises new questions about what really happened."
The change in dates is not only significant for English. It raises questions about the sworn testimony of the GCSB in High Court and Court of Appeal hearings.
It also raises a question over Key's apology and what it was intended to cover.
There was also a police investigation into the GCSB with a decision not to prosecute because there was no intent - the GCSB just didn't understand its own law.
But the question of the legality was raised between police and the GCSB on February 20 2012. A review by Wolfensohn led to it - wrongly - deciding it had not broken the law a week later.
It took Dotcom's lawyers to eventually point out that the error was clearly illegal.