National MP Judith Collins says she felt "absolutely hurt" after former Prime Minister John key stripped of the title "honourable," after she had been forced to resign shortly before the 2014 election.

She said Key had thrown her under a bus.

She also says that she had had the permission of Key to hold meetings with Chinese officials to discuss problems with meat exports during a visit to China that later got her into hot water. She had discussed it with him in the Koru lounge at Auckland before her visit to China, in front of her senior private secretary, Megan Wallace.

They are some of the revelations Collins makes in a memoir to be published this week, Pull No Punches.

Collins was forced to resign as a minister in 2014 after private third party emails surfaced from blogger Cameron Slater (Whale Oil) suggesting she may have been trying to undermine Serious Fraud Office chief executive Adam Feeley.

But it was widely seen at the time as the culmination of events that had begun months earlier over her activities in China. She had been accused of using her ministerial position and official visit to undertake activities that would benefit Oravida milk company, of which her husband was a director.

"The thing is John Key did know about it," she told TVNZ's Q and A today in an interview about the book. "It wasn't anything to do Oravida's business. It was to do with the meat exports that had been messed up by basically officials."

Asked if she felt Key had thrown her under the bus, she said: "Absolutely, that's how I felt."

"He couldn't remember the discussion we had had in the Koru lounge in front of my private secretary months before and then after he had done that, he then remembered it."

The revelations and accusations about the dinner with Chinese officials plagued the Key Government for some time.

Collins did not believe Key had been untruthful.

"I'd like to take him at his word that he genuinely forgot."

And she said that when she was forced to resign during the election campaign after the Cameron Slater email suggested she was "gunning" for the SFO chief, she understood that Key was trying to secure an election win for National.

She was not reinstated as a minister until the Chisholm report cleared her over a year later, but in the meantime, Key had removed the honorific "honourable" that all cabinet ministers and former ministers are entitled to use.

"At that time I felt very disappointed in him ... but I also knew that he was making a decision because if we hadn't done something or he hadn't done something I feel he felt that he could have lost the election and no longer been Prime Minister.

"I didn't feel terribly bitter. I certainly did feel disappointed, let down and he is a far more ruthless person than myself. I wouldn't have done that to someone else.

"But I also know that I did feel absolutely hurt when he took the honorific off me.

"That was a terrible thing to do when the last person that had been done to was Taito Philip Field who had served about six or seven years in jail."

Collins also said she does like the nickname "Crusher Collins" – acquired as Police Minister when proposed crushing the cars of street racers - because it is very one-dimensional.

"It gave people permission to treat me as less than human," she said.

She said she was careful in the book not to go into the past two years in the National Party.

"I have been careful not to destroy other people's careers."

She was looking at doing a sequel which might be called "Take No Prisoners."