The campaign was launched at Kings Langley Childcare Centre and was supported by Julie Griffiths from United Services Union (USU), Adam Kerslake from Unions NSW, Blacktown Mayor Leo Kelly and Blacktown MP Paul Gibson.

They say they want better than the current Commonwealth public servants' 12 weeks paid maternity leave and 40 weeks unpaid leave, and other schemes negotiated with employers.

Ms Griffiths, USU's director, Child Care, Women, Youth and Aged Care, said about 10,000 people had signed a petition to Prime Minister Kevin Rudd seeking six months' paid maternity leave.

``This is essential to help families achieve a balance in their work and health,'' she said.

'`Health experts and the World Health Organisation say breastfeeding for six months achieves optimal health results for babies.

'`We have asked for a government-funded system of six months' universal paid maternity leave, irrespective of whether they are casual, full-time, contractors or stay-at-home mums.''

Ms Griffiths said full wage replacement could be covered using a system of pooled contributions by employers, similar to the long service leave model that operates in the construction industry.

``This would involve employers paying a levy into a central fund to then be distributed much like superannuation,'' she said.

``This leave should include a base rate of pay provided by the Government with full wage replacement aided by employers.''

Working mum Daphne Longford said that six months' paid maternity leave would mean a world of difference for people like her. ``Like most women, I was forced to use up all my annual and long service leave to spend important time with my baby and still needed be able to pay the bills,'' she said.

Mayor Leo Kelly said he wouldn't underestimate the mums' determination to win the battle as ``the hand that rocks the cradle rules the world''.

Mr Gibson said a win would give mums more time to bond with their babies before returning to work.