The research, which surveyed 200 corporate financial advisers, found a further 20 per cent of advisers expected the drop out rate to be as high as 50 per cent.

Advisers forecast the majority of people dropping out would be from the 35 years old and under age group who would be saving for the first time.

The reasons given for this drop out were that they have other financial priorities such as paying off debts and buying a house, did not trust pensions and did not understand the benefits of a workplace pension.

Respondents suggested firms should actively encourage younger members of staff to join the scheme either by offering Financial Planning sessions or providing information on the benefits of pension schemes.

In a separate survey of employees, Aviva found only 14 per cent of 25-35 years olds said they had received any information from their employer on workplace pension schemes.

Aviva’s director of workplace savings Paul Goodwin said: “Our work with customers and advisers indicate that there is already a lot of consideration being given to planning for auto-enrolment but, at the same time, more thought needs to be given to how we engage with employees so that opt-outs are minimised.

“It is apparent that there is still quite a gap between the information given to clients and what employees actually feel they receive.”