The long-awaited report of the Pensions Commission is due to be published in November, but the battle to influence its findings goes on.

The Trades Union Congress (TUC) has today argued that increasing tax breaks for saving is not the answer to the UK's £130 billion pensions black hole.

Instead, the body – which speaks on behalf of many of the UK's trade unions – is calling for compulsion for employers and employees.

The TUC may have a point about tax incentives. There are already massive incentives for paying into a pension scheme, primarily in the form of income tax relief on contributions.

As the TUC points out, this benefits high earners more than people on lower incomes: because tax relief on pension contributions is paid at the rate you pay income tax on your earnings.

That means, for every 60 pence someone who pays the top rate of income tax pays into a pension, the government contributes an extra 40p.

Basic rate taxpayers get tax relief only at 22 per cent instead of 40 per cent.

The TUC claims that more than half of the £27 billion the government spends each year on tax incentives for savings goes on the savings of 2.5 million higher earners, with the rest distributed between 13 million ordinary taxpayers.

TUC general secretary Brendan Barber warned: "We already have huge incentives to save for retirement, but they are not working. Instead of the further help for the better off that new incentives would provide, the government should phase in compulsory savings for employers and employees."

The TUC's remarks are being widely viewed as an attempt to influence Adair Turner's Pensions Commission ahead of its final report next month.

Is forcing people to save for their retirements the answer? A 2004 survey conducted by the Association of British Insurers found that it was a popular option, with 70 per cent of 18 to 29 year-olds, 73 per cent of 30 to 50 year-olds and 79 per cent of over 50s in favour.

Employers are more divided, however. A recent study by the Engineering Employers Federation came out in favour of it. The CBI, however, is resolutely opposed, preferring to sustain a voluntary approach.

Business scepticism is hardly surprising: at present, employers are not obliged to contribute to employees' pensions at all. In addition, final salary pension schemes are closing at a very rapid rate, as businesses realise how much they are going to cost.

And what does the government think? Signals are mixed: David Blunkett and Gordon Brown have stressed the importance of keeping an open mind, pending the Turner report, but at a meeting at the Labour party conference last week, minister Stephen Timms was unenthusiastic, warning that the public would see compulsion as a tax.

As such, the TUC's intervention could be interpreted as an attempt to push a dwindling issue back to the top of the political agenda.

The Pensions Commission's interim reports have been sympathetic to compulsion to date, but government-appointed commissions have a noble history of refusing to opt for the hard choices in the final analysis.

Will this case be any different? With a £130 billion gap between what people save and what they need to live at stake, we can only hope that the Turner Commission will have the courage not to offer a fudge.