Claire Trevett: Clare Curran the canary in the mine for Jacinda Ardern

COMMENT: As with cats, ministers resort to fight or flight responses when the pressure goes on.

On the fight side are those who emerge tougher than tungsten from the pressure. They ride things out as best they can, take the consequences handed down, whether justified or not, and wait for a better day to dawn.

Judith Collins is one exhibit, Bill English and Helen Clark are others who have the intestinal fortitude to forge through hard times and ultimately triumph. The hard times simply make the redemption that much sweeter.

Others crumble under the pressure, such as Clare Curran whose resignation as a minister was announced on Friday morning following a trickle of mini-scandals

Curran had not yet reached the threshold at which Ardern should have sacked her. Her failure to disclose two meetings in official Parliamentary answers were mis-steps - not least because Curran was the Minister charged with transparency and open government, and they invoked that H word - hypocrisy.

But she had not misled the Prime Minister, nor committed a sin egregious enough to warrant sacking.

But she had reached the threshold at which she should have resigned. It will spark the inevitable speculation about whether there was something ahead that would have resulted in a sacking.

But on the face of it, Curran was simply conceding she was not up to the job of shouldering what was coming.

Ministers who make one mistake will always be branded a potential weak link and face greater scrutiny than their colleagues from the Opposition. It looks like bullying and sometimes it is. But neither side can cry foul because both do it.

In a brief statement, Curran said she had made mistakes but they had been amplified.

That is what all Oppositions do. When it was in Opposition, Labour too 'amplified' mistakes such as those of Judith Collins and Sam Lotu Iiga.

The resignation of Curran highlights the plight Ardern faced when Labour went into government.

Labour had only a skeleton caucus from 2014 to 2017, courtesy of its drubbing in 2014.

That left Ardern with a very small talent pool to choose from when it came to putting together her Cabinet. Only Damien O'Connor, Nanaia Mahuta and David Parker had served in a Cabinet.

None of her new first-term or even second term MPs amounted to a Steven Joyce, who was appointed straight into Cabinet by John Key.

Ardern had also made much of trying to reach a 50-50 gender split in Cabinet.

That was effectively impossible in the short term - without Curran there are just six women in Cabinet including Ardern and NZ First's Tracey Martin.

That will have impacted on Ardern's choices and was likely a factor in her decision to put Curran into Cabinet in the first place. It was also a factor in Meka Whaitiri's elevation, another who is now under the gun over an employment issue.

Ardern has transferred Curran's portfolios to Kris Faafoi, who has proved a competent hand in his other portfolios and is experienced on television.

Yet Ardern has kept Faafoi - who is deserving of a Cabinet place - outside Cabinet, leaving Curran's seat free. That indicates a reshuffle is in store and a woman is odds-on to fill that slot.

The first and second term MPs have had some chance to get some experience now, giving Ardern more options than she had a year ago. They include the likes of Deborah Russell and Kiritapu Allen. Those MPs should be at their sharpest.

And Ardern should ensure she has an early alert system and rescue plan ready for any other ministers heading to a Curran-like cropper.