The firefighters' union says an inquiry into Fire and Emergency (FENZ) can't wait until after the election, and a sacking of leadership needs to happen now.

A select committee report found FENZ had misled Parliament and mismanaged the purchase of 30 new fire trucks.

On Wednesday, New Zealand Professional Firefighters Union (NZPFU) members handed over a petition with more than 50,000 signatures to government at Parliament, demanding an inquiry.

It was firefighters' 64th strike in two years for better working conditions.

In response to the failings, National has vowed to make FENZ a departmental agency directly accountable to the Emergency Management Minister.

Labour and the Greens have both pledged a full inquiry into FENZ, while National said it is focused on moving forward.

Union national secretary Wattie Watson told Morning Report while she appreciated pledges for an inquiry, it could not wait.

"We're really disappointed that there has been such an outcry across the political spectrum about FENZ's conduct, and in particular the chief executive's.

"And yet, no one seems to be able to do anything, everyone's sitting on their hands."

Watson said National's re-election plan could work - however, she believed it didn't have enough "meat on the bones".

She said a shake-up cannot wait until the next government is formed, and she was concerned it wouldn't be an immediate priority regardless.

She said an immediate inquiry was needed to understand what went wrong.