Although we found some evidence for the extended weekend absence ... the proportion of days lost was marginal

Dr Jussi Vahtera, Finnish Institute for Occupational Health

Manual and clerical staff in the five towns studied had a combined total of 1.137m days off work due to sickness between Monday and Friday over the five years.

Weekend working appeared to be rare.

Rates of sick leave were lowest on Mondays, increasing up to Wednesdays and then remaining at the same level up to Fridays.

This was true for both sexes, and across all age groups in each year of the study.

The researchers, from the Finnish Institute of Occupational Health, found one-day sick leave made up just 4.5% of total sickness absenteeism.

And they estimate around 50% of absences which included a Monday or a Friday could be due to longer-term sickness that also affected weekends.

At any time during the study, 3.5% of male employees and 5% of female employees were on sick leave.

Men, younger employees and those in a lower socio-economic position were more likely to have extended weekend sick leave, though the pattern varied between the towns in the study.

'24/7 culture'

Dr Jussi Vahtera, who led the study, wrote: "From the managerial point of view, the key issue is the proportion of absenteeism which is avoidable.

"Although we found some evidence for the extended weekend absence - that is, absences which are provable not related to sickness, the proportion of days lost was marginal."

Dr David Holmes, senior lecturer in psychology at Manchester Metropolitan University, told BBC News Online the pattern would probably hold true for the UK.

"What used to be a week-day, weekend culture is now 24 hours, seven days a week."

He said that meant people no longer necessarily worked a strict five-day, Monday to Friday week, and they no longer saved all their socialising for the weekend - affecting the days people might take off as "sick leave".

Diane Sinclair, employee relations advisor for the Chartered Institute of Personnel and Development, said she was aware of surveys which showed people were more likely to be off sick on a Monday.

She added that "dress-down" Fridays were believed to have reduced absences on that day.

But Ms Sinclair added: "I don't know any organisations that would concentrate on Monday/Friday absences.

"They would look for patterns of short-term absences, which could trigger an interview with the employer."