Government grants should not be given to companies that pay staff low wages or avoid paying "fair" taxes, the Liberal Democrats have pledged.

The party's Holyrood manifesto, due to be unveiled on Friday, will contain a commitment that firms should not benefit from regional selective assistance funding if they fail to give their workers the living wage.

In addition, awards above £250,000 could be scrutinised by Holyrood's Public Audit Committee before the money is handed over to ensure "the recipient company pays a fair level of UK tax".

Liberal Democrat leader Willie Rennie has called on other parties in the campaign for May's Scottish election to match the commitments.

He was speaking as he campaigned outside internet retailer Amazon's plant in Dunfermline, Fife, after it emerged the company paid £11.9 million in tax on British sales totalling £5.3 billion.

Mr Rennie said: "For Scotland to be a fairer society where everyone has the chance to get up and get on, there cannot be one set of rules for massive corporations and another for everyone else.

"Tax avoidance rules and paying workers fairly should apply to both the Davids and the Goliaths of the business world. But at the moment corporations like Amazon are being rewarded for failing to pay their workers properly and for only paying measly levels of tax.

"If the other political parties are committed to reducing wealth inequality in Scotland, they should be guaranteeing that they will not dole out taxpayer support to these kind of corporations.

"Scottish Liberal Democrats will not pay government grants to companies if they do not pay the living wage or their taxes."

A Scottish Green Party spokesman said: "Three years ago Green Alison Johnstone challenged SNP ministers over the grants given to Amazon.

"It's good to see the Lib Dems eventually catching up with this issue but of course they were cheerleaders for Tory austerity, so their attempt to appear concerned about people on low incomes has zero credibility.

"The Scottish Greens manifesto commits to making government business support available only to those companies who plan to pay the living wage, avoid zero-hours contracts, recognise trade unions, reduce the gap between the highest and lowest paid, pay women and men equally and are environmentally responsible."