Former cabinet minister Jonathan Coleman delivers valedictory speech

Former cabinet minister Jonathan Coleman has delivered his valedictory speech in parliament.

An MP for more than 12 years and a minister for nine of them, Coleman revealed the way he was first appointed to cabinet by the then prime minister John Key, now Sir John Key.

"He wasn't about to enter into any debate," Coleman said.

"He said 'you're doing immigration, broadcasting, associate health and associate tourism. I'm the minister of tourism so you'll be doing all the work. Catch you Monday'."

Coleman said Key was "a great guy to work for".

"Ministers agreed priorities with him and if he had confidence in an individual he just let them get on with it.

"He was arguably the most talented politician we will see in our lifetimes."

Coleman, a GP before he came to parliament, recalled the occasion when Key slipped as he ran up on stage at a Chinese New Year festival in 2009.

"Returning to his seat next to me, he said his arm was a bit sore," Dr Coleman said.

"I advised him to take a couple of Panadol, forget about it and all would be well.

"The next day he rang to inform me his arm was broken in two places."

Coleman, who held senior portfolios including defence and health, had some advice for new ministers.

"They can sink or swim, they have to have big picture priorities to achieve anything."

Coleman is leaving parliament to take up the role of chief executive for a private health care provider.