Up to 1,200 separated Australian parents, mainly wealthy fathers, risk being stopped at airport departure gates as they leave for overseas holidays unless they pay outstanding child support.

Figures obtained by The Australian show that 482 parents were contacted by the Child Support Agency in the past financial year and ordered to pay up before going on holiday.

This year the number of people stopped is set to double.

Those who tried to slip out of the country were taken aside by Australian Federal Police officers and warned a travel ban was in place.

The CSA is now working closely with the Department of Immigration to better target parents with large debts who travel frequently. Specialist teams have been set up in Perth and Hobart this financial year.

The 482 parents contacted by the CSA had to pay combined debts of more than $6.7 million in 2005-06 before being allowed to leave the country.

A departure prohibition order gives the AFP authority to stop parents at the airport from leaving the country.

Lone Fathers Association president Barry Williams said he supported the system, which stopped parents "jumping the country".

"It had to happen because it’s not fair just to leave like that," he said.

Minister for Human Services Joe Hockey said the Government made "no apologies" for the crackdown, which was putting the interests of children first. "I am warning serious avoiders – pay up before you reach the departure lounge."

Departure prohibition orders are a measure of last resort but parents need to be aware of their debts before booking holidays, Mr Hockey said.

Parents can only leave Australia once their child support debts are paid or a suitable payment arrangement or security is put in place.

Since the program’s inception in 2001, 1151 parents with child support debts have cleared about $12.2 million before heading overseas.

"This is a very successful mechanism for collecting outstanding child support, of which many other countries are envious," Mr Hockey said.

"Some serious avoiders of child support believe they can escape their payment obligations by leaving the country.

"Obviously people are given ample opportunity to resolve their childcare debts before reaching an airport but it is important they know that they could be stopped," Mr Hockey added.

The Howard Government will spend $134 million over the next five years chasing parents who avoid paying child support. About 40 per cent of separated fathers pay only $5 a week. About 105,000 are using self-employment and cash income to understate their real incomes in a bid to avoid paying their full share.

A crack team of 120 investigators will spy on divorced dads who cry poor to avoid paying child support, using photographic and video evidence to expose them driving around in expensive cars and living in rich suburbs.

The Government has also made changes to the child support system, which include allowing divorced fathers who see their children one day a week to have their support payments cut by 24 per cent.