Lynn Millward, a lecturer in organisational psychology at Surrey University, has presented research into the impact of the clash of cultures between a fixed-term and permanent workforce.
With management consultant Lee Hopkins she has found that the increasing use of temporary contracts means that those with permanent jobs fear that although they are not casualised at present, they eventually will be.
She said: "They tend to over-commit themselves and work excessive hours to prove they are indispensable. The possibility of burn-out is huge.
"I think organisations run the danger of breeding more and more neurotic people.
"On the other hand, people on temporary contracts are less likely to be committed to an organisation and its goals.
"People become more self-interested and an organisation runs the danger of losing its substance.
"Also, fear of job insecurity must create stress and affect performance. "