ALMOST three-quarters of employers believe staff who "pulled a sickie" over the last week did it because of the heatwave, according to a recruitment agency.
Peninsula Ireland said there was a sharp rise in the number of complaints from employers about absenteeism as temperatures soared.
It said its advice line, which takes calls from employers on employment issues, took 1,809 calls since Wednesday about employees calling in sick.
This was a 77pc increase from 1,021 calls in relation to absenteeism the previous week.
The recruitment agency said queries were generally from employers who wanted to know how to deal with employees they suspected of lying about their absence.
Managing director of Peninsula Ireland, Alan Price, said an increase in "sickies" happens every time we are fortunate enough to have good weather.
"A total of 71pc of the employers we spoke to believed that their absenteeism was in relation to the heatwave," he said.
He said a classic example of a bogus sickie is when a worker calls in ill first thing in the morning but then updates their social networking site, saying what a good weekend they had out with their friends.
He said employers need to take a tough stance if they feel their workers are involved in "summertime skiving".
"Employees should also be aware that their actions may have a detrimental impact on workloads especially if it is a small business in question," he said.
"Ask yourself is it worth getting in trouble from your boss just for the sake of a couple of days of good weather?"
However, the Irish Small and Medium Enterprises Association, which represents 8,750 employers, said it had no increase in inquiries about sick leave.
"We haven't had any inquiries to our helpline about disciplinary action against staff on sick leave," said chief executive Mark Fielding.
"We've never had a spate of it, but then it's so long since we've had good weather."
He said some members were making provision for Euro 2012 next month by allowing employees do extra work in advance of matches so they could have time off to watch them.
The main employer group, IBEC, said it does not keep a record of trends in sick leave during good weather. However, the temptation to skive off will remain as forecasters predict temperatures around 18C towards the weekend.