Although nearly three-quarters of people in the UK think that pensions saving should be compulsory, only a quarter would agree if it meant lower take-home pay.

Compulsory pension schemes have been suggested as one way of reducing the predicted pension black hole.

The study by Association of British Insurers said opinion polls consistently suggested that some 70% of the public would support greater compulsion on pensions' saving.

But people who already do not save much towards their pensions are the most opposed to a compulsory pension scheme, the polls showed. Young and part-time workers also show little enthusiasm for compulsory pension schemes.

Some four and a half million workers who are most at risk of not having enough income during retirement are the most opposed to being made to save into a pension, the ABI estimates.

And the 70% figure of people who were happy with the idea of compulsory schemes fell to 50% when they were told they would likely receive less take-home pay.

The research found that the most popular option for compulsory saving was for both employers and staff to pay into pensions, with just over half thinking around 10% of their salary should be contributed.

The ABI found that support for a compulsory pension scheme was strongest amongst older workers earning in excess of £40,000 a year.

Joanne Segars, head of pensions and savings at the ABI, said: "This research shows that the argument for compulsion in pensions saving is not as black and white as it first appears."

"Once people start to understand the implications of compulsion and in particular realise that compulsion has to be paid for and is not simply free money, the arguments become less clear cut."

"Even supporters of compulsion tend to shy away from the suggestion that they should contribute more than they do at present."