The number of women on government boards has slipped below the 40 per cent target and a new report says men made up 75 per cent of new appointees within Tony Abbott's own Department of the Prime Minister and Cabinet this year.

The Prime Minister, who is also the Minister for Women, has assured voters he is committed to the gender diversity target but the opposition says the statistics should "set the bells ringing".

Decline: Female board representation is falling under Tony Abbott. Credit:Alex Ellinghausen

The annual Gender Balance on Australian Government Boards Report says overall female representation slipped from its peak of 41.7 per cent under Labor in 2013 to 39.7 under the Coalition in 2014.

The Coalition drastically slashed the number of board positions from 4039 to 3206 when it came into government as part of its deregulation agenda.