The right-wing senator is an intoxicating mix of unfashionable convictions, political intrigue, and a beguiling personal warmth - a combination not unlike the late Labor senator Kimberley Kitching about whom Prime Minister Scott Morrison has been so talkative in order to put Anthony Albanese under pressure.

But it is Morrison's questionable character that Fierravanti-Wells has lined up in the Senate on Tuesday evening branding the man who leads her party as "ruthless" and morally unfit.

Once again, we see that feelings about this PM tend to run most bitter in the people closest to him.

The words may differ but the tune is familiar.

Whether it be via excoriating "textimonials" from Barnaby Joyce - now his loyal deputy PM if you believe it - or ex-NSW premier Gladys Berejiklian, or through public comments from former PM Malcolm Turnbull or backbencher, Julia Banks, who magnificently critiqued Morrison's style as like "menacing wallpaper".

There are many more detractors within his own partyroom even if attribution is harder to nail.

Why is this inside knowledge a problem for Morrison? Precisely because he snagged the prime ministership by capitalising on its polar opposite. When people didn't know Morrison from a bar of sugar-soap, he was able to confect a persona to fill in the blanks - the suburban everyman, Sharkies fan, church goer. Morrison as both PM and daggy dad.

In a Senate speech just days from an election being called, Senator Fierravanti-Wells spoke of a "putrid stench of corruption" in the NSW division of the Liberal Party under Morrison's prime ministership and the iron grip of his "consigliere", Immigration Minister Alex Hawke.

As surgical strikes against Morrison go, the charge that he is, above all else a fake, was piercing, designed to say to voters, don't trust this man.

"He is adept at running with the foxes and hunting with the hounds," she railed, "lacking a moral compass and having no conscience ... he has used his so-called faith as a marketing advantage".

According to the senator, Liberal rank and file members in NSW are aghast at the murky power-plays within the party's factionally controlled councils.

"They don't like Morrison and they don't trust him. They continue to despair at our prospects at the next federal election, and they blame Morrison for this," she said.

"In my public life I have met ruthless people. Morrison tops the list, followed closely by Hawke. Morrison is not fit to be prime minister and Hawke certainly is not fit to be a minister."

Some voters will discount Fierravanti-Well's comments as "sour grapes" after losing her winnable spot on the Senate ticket. And there's plenty in that argument.

But two things are undeniable.

There is a stunning consistency in the harsh assessments of the in-camera Morrison by people who have worked with him, had dealings up close. These are first-hand testimonies by Liberals and cannot be so easily brushed aside.

And second, Morrison's government has yet again promoted a less-experienced man over a more qualified woman. Whether this is tin-eared or ideological almost doesn't matter.

Voters are gaining a clearer picture of the man behind the marketing with each passing day.