"To do that is a disgrace,'' he said, referring to the land tax changes, which were originally announced by South Australian Treasurer Rob Lucas in June but were revamped on September 10 in a second overhaul.

The September 10 revamp cuts the top rate of land tax to 2.4 per cent from 3.7 per cent from July 1, 2020. But the move keeps in place an aggregation measure to stop higher-end investors using complex trusts and other structures to avoid paying land tax. It is that measure that lifts the tax bill for many larger property developers, and which particularly vexes Mr Makris.

Mr Makris said Mr Pyne would bring extra clout to the push to try to stop the new land tax proposals.

"He will do a very good job. He will carry a lot of weight''.

Mr Marshall on Tuesday was unperturbed about Mr Pyne weighing into the issue now.

He said South Australian businesses were ''free to hire'' whomever they liked to represent their interests.

"All feedback is welcome as we embark on the biggest reduction in land tax in the state's history,'' Mr Marshall said.

Mr Marshall became Premier in March 2018 with an election victory over Jay Weatherill, ending 16 years of Labor rule. But a rising unemployment rate - the highest in the country - and disquiet from the traditional Liberal heartland over the land tax changes has caused some heartburn in the past few months.


Mr Makris, who in 2016 shifted his corporate headquarters to the Gold Coast in Queensland, was ranked No.69 on the Financial Review's Rich List with an estimated personal wealth of $1.31 billion.

Mr Makris spent almost five decades building up a vast empire from property development and shopping centre ownership after arriving as a teenager in 1964 in Adelaide from Greece. He started in business with one chicken shop.

Mr Makris said he still had an office in Adelaide and a residence but had shifted his corporate headquarters to Queensland because there were more opportunities.

"There needs to be some smarter people in charge,'' Mr Makris said. "The Gold Coast is growing much faster,'' he said.

Property Council of Australian SA executive director Daniel Gannon said on Tuesday ''we welcome a diversity and depth of voices as part of our fight for a fair go, including Christopher Pyne''.

Mr Gannon said the state government's ''risky land proposal has taken a sledgehammer to confidence and scared investment away from our state''.

Among the five property groups to have engaged GC Advisory's services are Precision Group, run by Shaun Bonett, also a Financial Review Rich Lister.

Under the land tax overhaul announced on September 10, the top land tax rate in South Australia of 2.4 per cent would still be higher than NSW at 2 per cent and Victoria at 2.25 per cent. But it is lower than Western Australia's 2.67 per cent, and Queensland's commercial property land tax at 2.75 per cent.

Mr Lucas said at the time about 92 per cent of ''mum and dad'' investors – 47,800 individuals – would pay less land tax as a result, while about 75 per cent of companies would pay less land tax.

Mr Makris said Mr Lucas should be sacked from his position and Mr Marshall needed to do better to stimulate business conditions.