Firms facing an "extortionate" rise in their business rates should appeal the decision, the Scottish Conservatives have said.

The party's finance spokesman Murdo Fraser said objections to decisions would "send a very clear message" to the Scottish Government.

Businesses are facing their first rate revaluation since 2010 after the Scottish Government announced a fresh 2012 revaluation would be postponed for five years.

Fraser said: "By formally appealing these increases, finance secretary Derek Mackay would soon realise just how severe a problem this is.

"He's refusing to listen to opposition parties and experts, but he might listen to the individuals affected.

"Latest employment figures again show Scotland is trailing behind the rest of the UK and this is becoming a stubborn and worrying trend."

He added: "If the Scottish Government doesn't heed warnings about firms going out of business as a result of these rises, the unemployment queues are only going to get longer north of the border.

"Derek Mackay seemed able to find tens of millions squirrelled away for budget negotiations so perhaps he could find some extra cash for hard-up businesses, too."

Independent assessors are calculating the rentable value of businesses.

The rate companies pay is calculated by multiplying the rateable value by a "poundage rate" set by the Scottish Government.

The poundage rate is due to fall from 48.4p to 46.6p in the next financial year but the threshold for large businesses to pay an extra 2.6p supplement is set to rise from £35,000 to £51,000.

A Scottish Government spokesperson said: "Our package of measures delivers a tax cut of £155m, which will help those who might be impacted by a revaluation. It will also mean that from April 1 more than half of businesses will pay no rates, seven out of ten will pay either no or less rates than they do currently, and the total package of reliefs we are offering will increase to more than £600m.

"The first step open to all those businesses who are concerned is to contact the assessor and discuss how they worked out the provisional value.

"Final valuations will be published in March and businesses have until September to appeal. That process is entirely independent and we would encourage firms take up those opportunities."