Mr Mackay has appeared to bow to the growing rebellion against soaring Scottish business rates
The Finance Secretary announced he is to offer firms hit by massive hikes further support amid a backlash against the SNP Government.
Mr Mackay has come under mounting pressure to freeze plans which will see some companies face a rise of up to 620 per cent in their rates.
Opposition politicians and industry leaders have warned of price rises, company closures, and job losses.
It follows the first revaluation of non-domestic property since 2010, which threatens to cripple shops, nurseries, hotels and pubs across the country.
Opposition politicians and industry leaders have warned of price rises and company closures
The Scottish Government must step up for Scottish businesses and it must do it soon
Mr Mackay has so far refused to buckle insisting local authorities could help with financial relief to those facing a rates hike.
But he is expected to make a Parliamentary statement today spelling out plans to help firms in key regions and sectors of the economy.
The move came as Tories prepared to grill him at Holyrood over the crisis, while splits have emerged in the SNP.
Former First Minister Alex Salmond has admitted some complaints over the rises are “legitimate”.
Leading nationalist hotelier Sandy Fraser warned the backlash would be as fierce as against the Poll Tax and could bring down the SNP administration.
Former First Minister Alex Salmond has admitted some complaints over the rises are “legitimate”
Mr Fraser, owner of the Oak Tree Inn on the banks of Loch Lomond, said: “For somebody that has always voted SNP I am bitterly disappointed that we are in this position.”
Pro-independence group Business for Scotland also stepped into the row calling for a “robust set of rates relief measures” to “protect jobs and economic growth.”
Chief executive Gordon MacIntyre-Kemp said: “Rates increases are an issue across the whole of the UK, but the Scottish Government has an opportunity to intervene and create a competitive advantage for Scottish businesses in direct comparison to the UK Government’s complete mismanagement of Brexit.
“The Scottish Government must step up for Scottish businesses and it must do it soon.”
Mr Mackay and Economy Secretary Keith Brown are due to meet an alliance of business leaders on Wednesday where they will face demands to halt April’s hikes.
Although revaluations are carried out by independent assessors, industry leaders argue action is needed now before former RBS chairman Ken Barclay completes a review of the system by summer.
Businesses will be able to lodge appeals against rate increases but the process can take up to three years.
Mr Mackay was due to be quizzed by Conservatives as part of Holyrood’s weekly topical questions before announcing his statement.
The party’s finance spokesman Murdo Fraser said: “He’s been dragged to parliament kicking and screaming after we forced him into discussing the issue with an urgent question.
“It was clear that a crisis was emerging but instead of acting the SNP sat back and tried to pretend that it had nothing to do with them.”
Meanwhile, Scottish Labour published an analysis suggesting universities would loose out because of a 25 per cent increase in the valuation of their estates.
The party’s economy spokeswoman Jackie Baillie said: “With each passing day the devastating consequences of business rates under the SNP is becoming clear.
'The Scottish Government must step up for Scottish businesses and it must do it soon'
“It’s time for the SNP to get a grip of this problem and come up with a solution that doesn’t penalise the public services we all rely on.”
But the Scottish Government said universities receive at least 80 per cent charity relief on their rates.
Mr Mackay also insisted he had already set out “a competitive package of measures” to help firms with £600 million worth of reliefs.
He said more than half of businesses will pay no rates next year and seven out of 10 will pay the same or less.
Mr Mackay added: “Before the new property values came out I took action to support business.
“Since then I have been listening to firms across Scotland and today I will set out further steps to support Scotland’s economy.”