The revelation has  prompted Bass Liberal MHR Andrew Nikolic to lobby federal ministers for a review of the system.

The debt has grown by 25 per cent since December 2011, or well above cost of living growth over the same period. 

It is greater than the  child support debts  in both the ACT and the Northern Territory.

The exceptional growth in Tasmania is taking place even though the number of parents involved has dropped from 41,000 to 37,000 since 2011.

Nationally almost $1.1 billion is owed in child support, involving about 1.4 million separated parents and third-party carers.

Details of the outstanding debt across the states and territories were provided to The Examiner  by the Department of Health and Human Services in Canberra.

The child support scheme is a $3.2-billion-a-year system, covering almost $40 billion in support payments since it  started in 1988.

Unemployed paying parents, and those who claim to be unemployed and who have their kids for less than 35 per cent of the year, pay a nominal $7.50 a week for one child, rising to a maximum of $22.50 a week for three or more children. The $7.50 would barely cover a packet of cereal.

Mr Nikolic said many Tasmanian parents who paid and received child support regularly told him there were problems with the system.

``The child support system was neglected under Labor, resulting in complexity, uncertainty  and friction between many separated parents,'' Mr Nikolic said.

``This is evidenced by over 2000 complaints relating to child support being lodged each year with the Commonwealth Ombudsman.

``I have had preliminary discussions with some of my colleagues, including the minister, and I believe we need to review the system itself.''

 NSW heads the nation in child support debt, with $324 million owed, followed by $287.4 million owed in Queensland and $233.3 million owed  in Victoria.

 Tasmania's total of $22,324,338 makes up 2 per cent of the national debt.