While accounts differ about the magnitude of the internal opposition – one account said only one MP registered their dissent, while others say four members raised their hands – it’s understood there was heated debate about the budget measure, which will raise $86 million a year through an aggregation overhaul targeting trusts, while also lowering the top rate at which land tax is levied from 3.7 to 2.4 per cent.

Those two measures remain at the centrepiece of the Bill that will be tabled in parliament this week – with Premier Steven Marshall giving notice today – despite a consultation process that saw 190 submissions received by Treasury – many of them critical of the budget revenue grab.

A Liberal source said it was noted that the vote was “not unanimous”, and that members of the party-room spoke against “key measures on the basis of fairness”.

But the Treasurer has been adamant the aggregation changes are, ironically, driven by a fairness impetus, and has long rejected any move to ditch them – or ameliorate their impact through a grandfathering clause.

Asked about party-room dissent, he told InDaily today that “cabinet and the party-room have approved the reform package in the usual way”, adding the focus was “now on the Labor Party to get off the fence and make up its mind”.

Labor, which is unlikely to announce its own position until next week, holds the key to the legislation’s fate, with crossbencher John Darley confirming he would only introduce amendments he mooted in InDaily last month if Labor backed the Bill in the Upper House.

If the Opposition opposes the legislation, Darley will do likewise, killing it off altogether.

Darley conceded it was “a forlorn hope” that his amendments would carry if the Government already had the numbers to pass the Bill, but insisted: “This whole thing’s got to stop, for the sake of the economy really.”

“I’m told real estate’s just stopped dead in its tracks, development’s stopped dead in its tracks… the sooner it’s all over and done with the better, I think,” he said.

Sources have described the party-room briefing as a “robust discussion”, saying some MPs are contemplating crossing the floor if the Bill proceeds.

It’s understood none flagged this at the meeting yesterday, but it’s widely believed that was due to a belief Labor will kill it off in the Upper House, with some MPs privately suggesting if the legislation returns with amendments they will tell the party-room they reserve the right to cross the floor.

The Greens, who back the changes, have been briefed by Lucas and believe Labor is every chance to pass the legislation.

MLC Mark Parnell told InDaily:“I’d be pretty surprised if on a social justice, tax minimisation measure, they didn’t line up.”

He said some critics of the changes had written to him arguing they had worked hard for their property portfolios, and his response was: “Good on you – pay some tax.”

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