The move follows months of pressure from business owners who say they may face making redundancies and even going to the wall over increases of up to 200 per cent.
Pro-independence group Business for Scotland last night became the latest organisation to call for intervention amid claims that the situation is “not manageable” for many firms.
Mr MacKay has previously ruled out intervention but will today unveil new measures to help firms in a statement to MSPs at Holyrood.
The Scottish Government last night said it will include a “further package of support that will help businesses in key regions and sectors of the Scottish economy to better deal with the impact of the forthcoming revaluation of business rates”.
The rate rises are the result of a controversial re-evaluation of the “rateable values” of properties by the Scottish Assessors Association, which is independent of government.
Firms in the North-east fear the changes as the revaluations took place before the impact of the oil price crash on the region.
Business for Scotland was founded during the last referendum campaign to provide a business platform for pro-independence firms, angered by the perceived pro-union bias of the CBI Scotland.
Chief executive Gordon MacIntyre-Kemp said: “We need the Scottish Government to step up and be the champion of the business community on rates and to propose a robust set of rates relief measures that protect business from rapid rates rises and therefore protect jobs and economic growth.”
The organisation, which has 4,000 members, said yesterday that some have reported their rates are more than doubling and branded this “not manageable”.
Mr MacIntyre-Kemp added: “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 group’s intervention follows comments made over the weekend by former first minister Alex Salmond, who said some Scottish businesses have a “very legitimate” case against business rate rises.
Mr Mackay insisted last night he has already set out “a competitive package of measures to give small and medium enterprises the security and confidence to grow in these tough economic times”.
He added: “Under the Small Business Bonus Scheme 100,000 properties will pay no rates at all next year and a further 3,500 properties will benefit from 25 per cent relief. This package means around 9,000 properties will be up to £7,000 a year better off than their equivalents in England.
It emerged yesterday that universities have also seen their rateable values go up. Although the institutions enjoy charitable status, Labour claimed the rate rises could leave them with increased running costs.