Whanganui MP Chester Borrows gets the last laugh on Parliament

Retiring Whanganui MP Chester Borrows stood before his peers on Tuesday and described himself as "that loyal old labrador you'll never know whether to pat on the head or boot up the arse".

Mr Borrows made the tongue-in-cheek comment during his valedictory speech in Parliament - his farewell as he steps down after 12 years in politics.

During his time in Parliament as a National Party MP, Mr Borrows has been Minister for Courts, Associate Minister of Justice and Associate Minister of Social Development.

He described these portfolios as issues he "believed in" as a former police officer and lawyer.

"This Government has made some response to the inequities of our justice system ... but that doesn't mean there isn't stuff we could do better.

"The trouble is much of our business in courts is conducted in a language completely foreign to those appearing before it."

Achievements he was proud of included securing integration of Wanganui Collegiate, helping secure government funding for the Sarjeant Gallery upgrade and seeing the Normanby realignment finished.

"But smaller wins on behalf of constituents fighting again bureaucracy are just as rewarding," Mr Borrows, currently, deputy speaker of the House, said.

He did not shy away from controversial topics such as the incident in March last year when he was charged with careless driving causing injury after a protest in Whanganui. Mr Borrows was found not guilty in May this year.

"I apparently ran over the toes of the aptly name Ms Treadwell (she didn't, did she?) when I had minister Paula Bennett in the car. Thankfully the matter was recorded in full technicolour by a [Wanganui Chronicle] cameraman - and it is the only time I have ever used the phrase 'Thank God for the media'."

Mr Borrows said he was grateful to fellow National Party caucus members who paid half of his legal bill.

Some pieces of legislation he had initially opposed but now supported, including the so-called "anti-smacking bill".

"In hindsight, the changes are working well and parents are much better at finding other ways of correcting their children."

Mr Borrows is also now a supporter of marriage equality despite voting against the bill, which opened the door for same-sex marriages in New Zealand.

"I have been privileged to officiate as a celebrant at the wedding of a gay couple and recognise that people who love each other and form families are the backbone of a strong society, and we should encourage that regardless.

"Sometimes you've just got to grow up and I have ... a bit."

He was unsure what he would do once he left Parliament - a keen artist, he has some commissioned paintings to finish and "a few odd jobs around the house".

Parliament will be dissolved on August 22, with the general election on September 23 where his Whanganui seat is being contested by new National candidate Harete Hipango, Steph Lewis (Labour), Nicola Patrick (Greens) and Alan Davidson for the Act Party.