DEADBEAT parents who avoid paying child support will be spied on by private investigators under a move being considered by the Federal Government.

Human Services Minister Chris Bowen said the national program would involve the Child Support Agency conducting covert surveillance on parents who evaded child-support obligations.

The move follows a year-long trial in which investigators spied on, and filmed, parents suspected of avoiding support payments.

The Sunday Telegraph can reveal the Commonwealth Director of Public Prosecutions will investigate six cases of parents and employers allegedly colluding to avoid child-support payments.

A further three cases have been referred to other areas of the Child Support Agency (CSA).

A spokesman for Mr Bowen confirmed the Government was considering making the spy program permanent to boost the national child-support scheme.

"These measures are about improving the integrity of the child support system and, importantly, deterring those considering avoiding their responsibilities," he said.

"While the analysis of the CSA's surveillance trial continues, the evidence to date suggests that optical surveillance could play a part in the investigation of child-support evasion cases."

Child-support avoidance is a serious problem in Australia. Last week, it was revealed that 28,000 parents had failed to make, or were behind in, support payments.

Parents were caught out after filing their 2007-08 tax returns to receive the $900 bonus. At the start of the "spying" trial, it was estimated parents owed around $1 billion in unpaid payments.

The trial followed a 2007 pilot program that targeted eight parents from NSW and Queensland.

After this test, the Government launched a 12-month trial with about 20 private detectives targeting suspect parents.

In answers to questions on notice by the Opposition, the Government revealed the cost of the trial had been $337,000.

It said evidence gathered from surveillance operations would form part of a broader investigation into a client suspected of evading payments.

The Government hopes the trial will result in successful prosecutions, which it believes will act as a further warning to both parents and employers defrauding the system.

"As at May 31, the trial has involved actual surveillance on 11 customers, and other customers were being considered," it said.

The Government warned that surveillance would be used only in the most serious cases.

Footage from covert operations would be used as evidence if a matter went to court, it said.

Liberal MP Cory Bernardi, who raised the issue in Senate estimates, said he supported moves to conduct surveillance on parents.

"I'm pleased the estimates process has embarrassed this Government into action, and I expect it to have the full support of the Coalition," Mr Bernardi said.

"I think these deadbeat dads are disadvantaging their own children, and that is not acceptable."

NO-FAULT divorce laws will come under scrutiny as part of a broader review of the Family Law Act, amid fresh opposition interest in re-examining the way the nation ends its marriages.

A spokesman for Attorney-General Robert McClelland said the wide-ranging investigation, due to report by the end of the year, would take in all components of the act, including current grounds for dissolutions of marriage.

The requirement for a review was built into family law amendments passed by the Howard government to encourage shared parenting after divorce, and is being undertaken by the Australian Institute of Family Studies.

"They're examining the entire Family Law Act and they will make recommendations to government at the end of the year," the spokesman said.

"Once we get the recommendations of that review, we'll consider further action."

Opposition frontbencher Tony Abbott, the Liberals' most high-profile Catholic, has put the issue back on the agenda by calling in a forthcoming book for couples to have right of access to fault-based divorce.

Yesterday, deputy Opposition Leader Julie Bishop said the party would hear Mr Abbott out if he sought to change party policy on the issue.

"What Tony's doing is putting forward, I gather, his personal views on a particular matter and we'll debate them if he wants them to become part of our policy," Ms Bishop told ABC TV.

But she predicted a "healthy and robust debate" if he did.

Until 1975, a marriage could be dissolved only if a couple were separated for more than five years or one party proved fault

by way of adultery, desertion, cruelty, habitual drunkenness, imprisonment or insanity.

After that change, marriage laws were relaxed and the need to prove fault was eliminated, leaving irretrievable differences as the sole grounds for divorce.

Mr Abbott's proposal would resurrect adultery, cruelty and other grounds for divorce as an option for couples, to exist in parallel with the existing no-fault system.

The Howard government minister and current opposition families spokesman has said it should become harder to divorce, in recognition of the importance of the marriage contract.