Four-year political terms may not necessarily ensure delivery on campaign promises.

The Government's considering a referendum at the next election - to let voters decide whether to add a year on to our political terms.

It's argued allowing Parliament to take more time with its policy decisions could lead to stronger laws.

But constitutional law expert Graeme Edgeler says we don't have many one-term Governments to begin with - and many in fact, last three terms.

He says most get re-elected.

"Labour and Jacinda Ardern got six years to implement their policies, the last National Government had nine years to do it."

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