Shane Jones makes outrageous claims about National Party donations probe in Parliament

New Zealand First Minister Shane Jones has outrageously weighed in on the investigation into National Party donations.

The extraordinary scenes in Parliament on Wednesday afternoon added to a string of New Zealand First ministerial mishaps in recent times.

Jones' incredible comment about the Serious Fraud Office (SFO) probe into the Simon Bridges-led party was made under parliamentary privilege and therefore protected from threats of prosecution.

"We will study every single step they take to ensure because it's the National Party, it's not whitewashed," he said.

"We will ensure that happens. This is incredibly serious and people may very well go to jail."

But the SFO is protected by a fundamental of New Zealand's democracy known as 'constabulary independence', meaning politicians can't get involved in how it chooses to uphold the law - it's sacred.

"He's going to stand and guide the SFO while they do their work - what an extraordinary thing for a Cabinet Minister to say," said National's Paul Goldsmith.

Jones has spent the week over-stepping the mark and getting himself in trouble. On Thursday he ramped that up big-time - and he's not the only New Zealand First minister making extraordinary claims.

Ron Mark appeared to use a late-night debate to issue a threat to spill dirt on National MP Mark Mitchell.

"There goes Mr Mitchell over there, yabbering away... Bring it on, Mr Mitchell, I've a lot of information for you to share with the country," he said. 

Mark is already in trouble, receiving a Prime Ministerial telling off after Newshub revealed video of him appearing to drum up New Zealand First votes at a veterans event he attended as Minister.

"I have shared with him my view that when speaking in a Ministerial capacity, references of a party political nature should be left at the door," Jacinda Ardern said.

It's the Parliamentary equivalent of being sent to the head teacher's office.

"I told her I will be a bit tighter in future," Mark confirmed.

The scolding didn't go unnoticed by Bridges, who seized the opportunity to make his own off-side remarks.

"Is she making excuses for her ministers' appalling behaviour because she's a little bit stressed with the rigours of Government?" Bridges asked in Parliament.

The parliamentary tiff eventually exasperated the Speaker Trevor Mallard, who commented, "I'd just like a day to go by..." before sitting back down and smiling.

He won't be the only one urging Ministers to keep themselves in order.