Andrew Little - who first entered Parliament in 2011 - has confirmed he will not take a list seat and will retire from politics.

Shanan Halbert is next on the list, and would be able to remain.

"I'm grateful for the opportunities my country and party have given me to serve the community," says Little.

Little first entered Parliament in 2011, and led the party in the lead-up to the 2017 election but stood down to make way for Jacinda Ardern's leadership in the face of poor personal polling.

He says with Labour going into opposition, it's important to give the next Labour government every opportunity "to hone their skills and cement a strong team".

"The Labour movement is bigger than any caucus or parliamentary term, and bigger than any individual.

"Labour stands for the fundamental values of millions of New Zealanders: a fair day's pay for a fair day's work, opportunities for the many not just the few, and respect for all people and communities."

Little has held high-profile portfolios including Health, Justice, Immigration, Defence, Courts, Workplace Relations, Treaty Negotiations, Public Service.

He has also held more specialised roles as Minister for Pike River Re-entry, and the Government's Response to the Royal Commission's Report into the Terrorist Attack on the Christchurch Mosques.

-RNZ.