SICK employees who still go to work cost the Scottish public sector tens of millions of pounds more than those who stay at home, an expert has warned.

Fred Best believes "presenteeism is the new absenteeism" because biting austerity cuts means more and more people turn up for jobs even when they are unfit to do so.

Mr Best, the founder and chairman of Work4Wellbeing, a company that seeks to boost well-being in the workplace, warns those who do not stay home are now costing employers one-and- a-half times as much as those who do.

Citing a recent study from the Work Foundation, Mr Best said: "In times of austerity, when people are frightened for their jobs, they are likely to turn up even if they are struggling.

"But they should be asking ­themselves, 'Should I be driving that heavy machinery today, or making these huge corporate decisions that affect people's lives?'"

Unions and managers have both long worried that sick workers are reducing productivity by spreading germs or making mistakes.

Unison has carried out a survey of its public-sector members. It found one in four said they had worked while sick over the last month and that 60% had done so over the last year. Some 27% of those who did so cited fears of repercussions from their manager, but most said they had gone in sick because they did not want to let down colleagues.

Unison said the survey dismissed allegations of a "sickie culture" in the public sector.

Dave Watson, its Scottish organiser, and Mr Best are both speakers at an event called Tackling Absenteeism In The Public Sector In Scotland: Prevention And Health Promotion on Thursday.

So, too, is Angela Cullen, assistant director at Audit Scotland. Last November her organisation found that local authorities alone lost two million working days to sick leave in 2012/13 at a cost of more than £220 million a year to the tax payer. However, the Work Foundation's claim that presenteeism costs one and a half times as much as absences would suggest it would take the extra costs figure to £330m.

A spokesman for the Convention Of Scottish Local Authorities said: "There is no evidence presenteeism is a problem in councils and the wider public sector.

"Absenteeism statistics from Audit Scotland, while showing a modest improvement in attendance management in councils for each of the past three years, do not demonstrate that this is anything other good practice and an appreciation on behalf of the workforce that their health and wellbeing is paramount".