Forty years ago, fewer than one in 30 working-age adults relied on welfare payments as their main source of income. Today the figure is one in six. The Government now wants to stem this increase.

Two of the key factors driving the growth of welfare dependency have been the increased numbers claiming Disability Support Pension and Parenting Payments. A cabinet blueprint proposes reforms to both these benefits.

The Labor Party and some vociferous welfare lobby groups seem set to oppose the changes but the case for both reforms is compelling, and public opinion is behind them.

The proportion of the working-age population on DSP has doubled since 1981. Although Australians have been getting healthier, the number of people under 65 defined as incapable of working has swollen to more than 700,000 (much higher than the number of unemployed). Many of these people are really "hidden unemployed" rather than disabled.

Half of those entering DSP each year are long-term jobless transferring from unemployment benefits. Because DSP pays more than Newstart and requires no mutual obligation, it is more attractive to claimants, and because it gets hard-to-place clients off its books, it also suits Job Network providers when claimants switch.

Most of the increase in DSP rates has little or nothing to do with incapacity. One-third of claimants cite musculoskeletal complaints that are often quite minor. Another quarter have psychological problems that may or may not be debilitating.

Many DSP claimants are older men with limited skills who have had difficulty finding work. They should be helped by reforming the labour market laws to generate more jobs, but for the past 30 years they have instead been shunted on to the disability pension and then forgotten. Once on the pension, claimants rarely come off until retirement.

The Government wants to tighten the definition of incapacity to put a stop to this slippage from unemployment into disability. It has public backing. A 2003 ACNielsen poll for the Centre for Independent Studies found nearly two-thirds of the public wants tighter rules.

Groups representing the disabled should also back this reform because limiting DSP to those who genuinely cannot work would release money that could better be spent improving support services for those who really do need help, and for their carers.

Much the same arguments apply to reform of the Parenting Payment. Although many lone parents work, half rely on the Parenting Payment as their sole or main source of income. As with DSP, the payment is more generous than the unemployment benefit and there is little mutual obligation required. Under present rules, sole parents are entitled to stay on welfare until their youngest child reaches school-leaving age. Many do just that. The average time sole parents spend on welfare is 12 years, during which time their skills erode and work habits attenuate. When entitlement eventually runs out, many are left unemployable.

As with disability, so with the rearing of young children; nobody resents giving help where aid is really needed. Very young children benefit from having a parent at home to look after them and it would be wrong to push sole parents into work while they are still caring for babies and toddlers.

But many parents return to work when their children start school and there is no reason why sole parents on welfare should not do likewise. Australia is one of very few countries where sole parents are not expected to re-enter the workforce once their children start school - the Americans and all the continental European countries insist on it as a fair and reasonable requirement.

Public opinion also sees this as reasonable. The ACNielsen survey found 84 per cent think single parents on welfare should work part-time once their children start school and government research found many sole parents agree with this. With both the DSP and Parenting Payment, therefore, the case for reform is compelling. We can nevertheless anticipate fierce resistance from opponents.

Two years ago, when I suggested single parents with school-age children should work part-time, the chair of Catholic Welfare Australia condemned the idea as "staggering in its harshness" and a leading sole-mothers activist warned of "homelessness and starvation for infants and mothers and more beggars in the street".

We can expect more such hyperbole in the coming months as opponents of reform seek to cloud the issue with emotional fog. We shall hear that the infirm are being forced to work and that sole parents are been driven into poverty. But all that is being proposed is that people who are capable of self-reliance should be expected and helped to find work. This is not only sensible, it is long overdue.

Professor Peter Saunders is social research director at The Centre for Independent Studies and author of Australia's Welfare Habit (Duffy & Snellgrove).