Security services firm ArmorGroup said the survey of all sectors revealed that one in 10 UK-based firms fail to insure their staff or other critical company assets when they work abroad.
Only three provided insurance cover for workers based in high-risk regions such as Iraq and Afghanistan.
Construction and transport firms are least likely to insure their staff or assets abroad, according to the study.
The report warns that firms are leaving themselves open to litigation over duty of care to their employees.
Neil Young, managing director of ArmorGroup's risk management division, said: “UK workers can face a range of threats irrespective of whether they are employed in a country such as Iraq or a seemingly safe European state.
“It is the duty of employers to ensure that they receive the necessary training and support before being sent abroad and are given the right level of insurance and protection when they are there.
“Staff should be confident that they and their families will receive appropriate levels of care should the worst happen - in fact they should insist on it.”