Veteran National MP Chris Finlayson has confirmed he will leave Parliament in the New Year.

"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," Finlayson said in a statement.

"I was honoured to serve as Attorney-General, Treaty Negotiations Minister, and Arts and Culture Minister during the last National Government under the leadership of Sir John Key and Sir Bill English."

Finlayson said his career highlights as a minister included progressing the Tūhoe settlement, reforming intelligence legislation and representing New Zealand at the International Court of Justice.

"It's with pride that the National Party in its nine years of Government settled over 60 treaty claims.

Finlayson, who was appointed a Queens Counsel in 2012, said he would re-join the Bar.

He will give his valedictory on December 18, with his final day in Parliament in January next year.

Parliament's Speaker Trevor Mallard let the cat out of the bag earlier today in the House.

During some interjections during question time, Finlayson made a comment, to which Mallard responded: "Mr Finlayson, you can include that in your valedictory if you want to be in the House on the 18th."

Advertisement

Finlayson's plan to resign this year has been one of the worst-kept secrets.

Finlayson's name came up in a taped conversation between National leader and rogue MP Jami-Lee Ross over which MPs were the "obvious" ones that were leaving.

He said at the time he wasn't in the least offended and had made it clear he was preparing for a return to his previous legal career.

National Party Leader Simon Bridges said Finlayson was one of Parliament's smartest MPs and had been an "incredibly successful Minister. He will be a big loss to the National caucus".

"Chris has been a great and often forthright colleague whose counsel was sought regularly by colleagues and by successive National Party prime ministers and leaders, including myself," Bridges said in a statement.

"I am sorry to see him announce his resignation from Parliament but am sure he will go on to have a successful career post-politics."