Jacinda Ardern to keep power from Winston Peters 'until last second' - Tova O'Brien

At any moment now, Prime Minister Jacinda Ardern could go into labour with her first baby.

As soon as she arrives at hospital, Acting Prime Minister responsibilities will begin for Deputy Prime Minister Winston Peters.

But until then, Ms Ardern remains in charge - and she seems determined to hold on to power. Newshub political editor Tova O'Brien joined The AM Show on Wednesday to discuss the succession.

"She is not giving up the reins of power a second before she has to," O'Brien told host Duncan Garner.

"There are a couple of reasons for that. There's probably an element of the Winston Petersness in public perception about him taking over as Prime Minister.

"I also think she's talked in the past about not being the first woman to multi-task, she's got the most powerful job in the country, she wants to hold onto that job... until she can't."

Briefly freed from the Prime Minister's watchful eye, members of the Government are expected to act responsibly. But O'Brien says this might be difficult for some MPs.

"I think everyone will be on their best behaviour. I think her caucus loves her, Winston Peters appears to love her as well, I think they're all going to be trying to behave themselves as best they can," O'Brien says.

"But trying is one thing... You never know what's going to happen down here. This is controlled chaos at Parliament, so at any minute anything could happen.

"And with Winston Peters you never know which Winston Peters you're going to get so he might set out to behave himself, but who knows."

But Mr Peters won't be given a free reign in power.

"He's the Acting Prime Minister, she is going to be consulted over high-level stuff," O'Brien says.

"The prime minister is still the prime minister."