Departing National MP Chris Finlayson won't compare Simon Bridges to 'extraordinary' John Key

Departing National MP Chris Finlayson wouldn't give Simon Bridges the same level of admiration as John Key when asked to compare the two.

Mr Finlayson, a former New Zealand Attorney-General and Minister for Treaty of Waitangi Negotiations who is retiring from Parliament in January, had been describing his respect for former Prime Minister John Key on RadioLIVE's The Long Lunch when he was asked how Mr Bridges, the current leader, compared.

After hesitating, Mr Finlayson said leaders like John Key weren't common.

"You'd get a John Key every 50 years. I mentioned [former National Prime Minister Keith Holyoake] earlier in the interview, and John Key is in that calibre," he said.

Mr Finlayson said Mr Key had been an "extraordinary leader" with a "positive, active personality".

"I was, and would never have been, nothing without the support of John Key... he had a can do attitude and positive attitude, and I count myself very lucky to have had an opportunity to work with him," he said.

But he pushed back on if he had nothing nice to say about Mr Bridges, noting he had had a difficult year with the fallout of the leaking of his travel expenses.

"We will see how Simon goes over the next little period... It's early days yet. We have a very good team in here. I think he has had a really tough year with that very sad Jami-Lee Ross incident, so I think he will be looking forward to a good Christmas break" he said.

Mr Finlayson was one of the National MPs caught up in October's Jami-Lee Ross saga, after Mr Ross released a tape of him talking with Mr Bridges, where the leader said some of his MPs needed to go.

"I reckon there's three of our MPs not bringing up obvious ones like [Chris] Finlayson or [David] Carter - but actually we just want them to go," said Mr Bridges.

Following the tape's release, Mr Finlayson confirmed that he would soon be retiring from Parliament to return to a legal career, but denied that his decision was linked to Mr Bridges' comments.

"Any suggestion that I am upset about the tape is just wrong," he told Stuff at the time.

On Wednesday, Mr Finlayson said his retirement would happen in January after giving his valedictory speech in December.

"It's been a real privilege to serve as a Member of Parliament since 2005, nine of them as a Cabinet Minister. I have greatly enjoyed my time here, and I am very grateful for the opportunities that I have had," he said.