Key Points:

On Monday night, Katherine Rich performed one of the last actions of her nine years as a National Party MP. She went to the dedication of a new "Rainbow Room" at Parliament to recognise gay, lesbian and transgender New Zealanders.

It was true to form for the woman regarded as the National Party's Jiminy Cricket over the past nine years - prodding its social conscience.

Katherine Rich's maiden speech was a paean to her place in New Zealand and her generation. "I am Katherine Rich" she began. "A sixth generation New Zealander of Scottish descent and my clan is Munro."

She made a vow to her family in that speech - pledging they would always come first and she would leave "with all my family relationships intact".

She also made a vow to herself: "I intend to do what is in my heart. I will have my own thoughts, my own style."

The first ended in her decision to leave Parliament to give her more time with her children.

The second pledge ensured she was noticed while she was in there.

Ms Rich re-read her maiden speech to do a stocktake before she started on her valedictory. She has, she says, "never hesitated to speak up".

There was the anti-smacking bill, for which Katherine Rich was a lone voice until the compromise was reached. It was not a "fun time" says Rich, but she is proud to have been part of the law change.

The starkest example was her refusal to back Don Brash's policy to require mothers on the DPB to work or have their benefit cut off. She was dumped from the welfare role and demoted.

She says now this was "probably not a career highlight, one might say". But she could not in all conscience back that policy.

"For me, demotion was preferable to having to explain why I, as a mother with all the support in the world, was going to tell a DPB mum to park her baby in childcare to go out and probably net $5 an hour. I didn't explain that at the time, and probably looking back I got into trouble more over what I didn't say than what I did. Because I said very little at the time."

She says Labour MPs have questioned "whether I'm in the right party".

"Usually they're trying to be kind. But I understand totally where I fit in the National Party tradition. I'm part of a smaller liberal tradition within National."

She cites Ralph Hannan, MP from 1946 to 1969, Tom Shand in the 1960s, Marilyn Waring in the 1980s and her contemporaries Clem Simich and Roger Sowry as part of that tradition.

Labour MP Steve Maharey sees her as somewhat of a caucus conscience.

"I've always thought of Katherine as someone who must be right on the left edge of National. I admired her stand on Brash's welfare policy. I thought that was pretty gutsy. She's her own person and thinks her own thoughts, she knows what she believes in and stands up for it. A lot of those thoughts are very close to where my views are."

She is perplexed by those who think she faced ongoing battles with her own party. People who have their own style are often seen as "lacking in discipline" she says.

"I have been true to what I said I would do, but I've certainly done it within a National framework. People tend to concentrate on those votes where I have differed from the majority of the party, But I voted with the party more than 3000 times. I've never crossed the floor and I have upheld every caucus decision."

She lists Maurice Williamson and Lockwood Smith as stalwart defenders of the sanctity of a conscience vote.

"Often I found those who defend a members' right to vote according to his or her conscience would be those to the right ... I don't think Maurice will mind me saying he's to the right of me."

There is also a sense of mischief. It was Rich who was first to holler "Hi-de-hi!" in Parliament when Rodney Hide stood in his yellow jacket - reminiscent of those worn by holiday camp staff in the British sitcom Hi-De-Hi. She couldn't resist, she says - "I am a child of the 80s."

Similarly, she enjoys having Labour's Darren Hughes on. After he gained his first ministerial post - as Statistics Minister, the least controversial portfolio in government - she leaped in to ask : "How many parliamentary questions has he answered since becoming minister?"

Her work has earned her a disparate range of friends. Labour's Mahara Okeroa "is the only person who could call me Kath-Girl and get away with it". There is the Maori Party's Pita Sharples, and from NZ First Doug Woolerton and former MP Brian Donnelly were "huge support" during the debate over the anti-smacking law. Green MP Sue Bradford found an ally in Rich trying to get support for the anti-smacking legislation and a bill allowing mothers to keep their babies longer while in prison.

She and Don Brash have also stayed in touch: "I'm having yum cha with him on Saturday.'

Rich is confident National is in safe "classically centre-right" hands. It's the only time she indulges in a jab at what National went through in 2004 and 2005:

"It's not trying to be the Act party. I think both John Key and Bill English have a strong social conscience. It makes me feel very confident about the future because when it comes to policies relating to welfare or education - those social areas, that they're going to keep a good course."

She admits to some disappointment at leaving just when National faced a chance of getting into government.

"I know people are convinced there must be a different reason. But, as John Key says, 'it is what it is.' I dunno. There are parts of your role as a mother you just can't delegate and you just have to be there and I feel strongly about that."

She says she doesn't have any firm plans. Someone suggested a book, but "I don't think political books are ever very insightful or interesting. Imagine seeing your own face in the bargain bin at The Warehouse".

She sounds only slightly abashed when she's subsequently told Steve Maharey is writing a book. One last shot in - even if it was inadvertent.

* Age 40.
* Married to Andrew.
* Combined they have four children, Jonathan, Georgia, Daniel and Emma.
* BCom, BA, University of Otago
* Project analyst, Ministry of Agriculture, Palmerston North
* Project analyst at Foundation for Research, Science and Technology, Wellington
* Marketing manager, knitting yarns division, Alliance Textiles Ltd
* General manager, Silverstream Ltd, Dunedin
* National MP 1999-2008