The account purports to belong to the Hutt Valley Chamber of Commerce. The controversial tweet was noticed on Thursday night, and quickly garnered dozens of outraged responses.

"I'm a member of @HuttChamber. This is a disgrace," tweeted Labour MP Trevor Mallard. "It is a lie and the majority of chamber members will be outraged by the political bias."

Others pointed out the tweet had Ms Ardern's age wrong (she's 37) and suggested the group had breached electoral laws by not including a promoter statement.

National MP Chris Bishop said the tweet was not acceptable, and he'd let the chief executive know.

Mr Mallard later said he had "spoken to the Hutt Chamber CEO. He has made it clear this is not a Chamber controlled account. The logo is dated."

The Twitter account is not presently linked to from the Hutt Valley Chamber of Commerce website, but appears to have been removed sometime since Wednesday night. Google's cache of the group's website - a snapshot of how it looked on Wednesday night - shows the Twitter account was still present when the tweet was posted.