Opposition MPs are calling for National MP Judith Collins to resign.
Nicky Hager's book Dirty Politics said Ms Collins gave National-aligned blogger Cameron Slater the name of a public servant, who then became the target of a smear campaign in his blog.
Ms Collins has admitted telling Slater the name, but says it was public information.
Labour MP Grant Robertson says Prime Minister John Key should sack her as a minister.
"This is a gross abuse of the power that a minister has... The fact that John Key refuses to sack her confirms that this is the kind of politics that he condones and supports."
Mr Robertson said the smear campaign was designed to be a distraction from the story about Bill English claiming housing allowances, and there was no evidence that the staff member had done anything wrong.
Green Party co-leader Metiria Turei and Labour's Phil Goff on The Nation today both called for Ms Collins' resignation.
Mr Hager's book alleges the PM's office used its knowledge of secret SIS documents to tip off Mr Slater to attack the Labour leader in the 2011 election campaign.
Mr Goff accused Mr Key of lying about knowing about an Official Information ACT request to the SIS.
Mr Goff said Mr Slater's OIA request was answered within a day, which was unheard of, while other media had to wait.
Mr Slater, who also appeared on The Nation, said he had frequent contact with Ms Collins.
"She was immensely supportive during the passing of my mother. She's earnt the right to be called a friend."
He had received death threats following the release of Mr Hager's book, Mr Slater said.
Mr Hager released his Dirty Politics book on Wednesday.
It is based on emails to and from Mr Slater, which the blogger says were stolen when his computer was hacked.
Mr Key has trashed the book, describing it as "a bunch of baseless allegations".
source: newshub archive