Prime Minister John Key has defended misleading the public over text exchanges with blogger Cameron Slater, saying he cannot be expected to remember all his texts.

Photo: RNZ / Diego Opatowski

Mr Key has faced criticism for twice yesterday saying he had not been in contact with the right-wing blogger about the inquiry into the Security Intelligence Service (SIS) when the previous night he had had a text exchange with the blogger.

Read the exchange here

He first told reporters he had not been in contact with Mr Slater over the report by Inspector-General Cheryl Gwyn, and then repeated that in Parliament. Late yesterday afternoon he had to correct his answer in Parliament to confirm he had been texting Mr Slater on Monday night about the matter.

However, the two men did not talk about the report itself, he said.

"My communications with him are quite clear. They're gossipy but they're about Phil Goff's breach of the confidentiality ... that's not something I'm guilty of."

Mr Key said he deleted his text messages and he could not be expected to remember them.

"You're now asking me, in a period of three months where I've dealt with an election campaign, where I probably deal with, I don't know, a thousand text messages a day from hundreds and hundreds of people, you're now telling me I have to remember exactly the number.

"And if I give you a number and I'm wrong you'll go and crucify me. And that's exactly the point. It's not fair on me to do that and expect that."

Photo: Supplied

However, senior minister Steven Joyce appears to have more confidence in Mr Key's ability to remember at least the content of his text messages.

Green Party co-leader Russel Norman asked in Parliament how Mr Key could be sure other communications between himself and Mr Slater did not touch on the SIS report.

"On behalf of the Prime Minister, I'm assuming he remembers the content of the conversations," Mr Joyce said.

Meanwhile, Opposition MPs say Mr Key needs to apologise for misleading the public.

Labour leader Andrew Little said Mr Key's behaviour is unbecoming as Prime Minister.

"John Key lied to the gallery on Tuesday when asked the question about whether he'd had contact with Cameron Slater," Mr Little said.

"He lied in the House. He then corrected his lie in the House. He lied about the correction about the lie. This just goes on and on. The guy cannot tell a straight story."

New Zealand First leader Winston Peters said Mr Key had no excuses.

"He simply did not tell the truth in circumstances where either he's got a very serious memory problem most of the time when attention goes on him or he is, you know, behaving like what you expect a lot of people in Wall St to behave," Mr Peters said.