One in four workers say they are expected to answer calls or emails outside of office hours.
A new University of Limerick report has looked at the impact of technology on over 2,000 employees in the finance and tech sectors.
It found that nine in ten feel employers don't make an effort to stop them over-using technology to work.
The Financial Services Union is calling on the Government to introduce legislation giving employees the 'right to disconnect'.
FSU spokesperson Gareth Murphy says the 'always-on culture' is a major factor in work-related stress.
"New devices, technology, smartphones, tablets, iPads, etc. - people are answering calls in the evenings and it's blurring the lines between work and home life or social life," he said.
This is leading to both an intensification of work and, as a consequence, leading to work-related stress and other mental health issues.
He says the mental health of employees must be protected.
"If there is working conditions that are creating health and safety issues like work-related stress, we have to find the root causes and get rid of them.
"One of those root causes is out of hours use of technology and smartphones and that always-on, you-have-to-reply culture that permeates many offices."