The bill is part of a drive to provide affordable childcare

The Childcare Bill, due to be published shortly, will also tighten rules about those who provide childcare.

It is part of a drive for an affordable network of nurseries and childminders.

The Lib Dems said the bill should not force parents back to work - or give local authorities extra duties without the cash to deliver them.

'Children's wellbeing'

The legislation will require carers of children aged up to eight to register with watchdog Ofsted, while carers of older children can register voluntarily.

They will have to register in a new Childcare Register which will keep track of childminders and other groups looking after school age children.

It puts children's wellbeing and their life chances at the heart of legislation Beverley Hughes Children's Minister

This will include rules covering the suitability of people working as childminders and other health and safety issues.

It is also expected to set out requirements for acceptable ratios of children to adults and suitable qualifications for childminders and nursery staff.

Children's minister Beverley Hughes said it was the first bill devoted to under-5s and childcare.

"It puts children's wellbeing and their life chances at the heart of legislation and it brings childcare into the mainstream of what a modern welfare state should be," she told BBC Radio 4's Today programme.

She said local authorities would be required to "facilitate the market" to make sure there were enough places for children whose parents want to work.

Business advice

Childcare is provided by the private voluntary independent sector as well as nursery and other places in the maintained sector.

the fear is that local authorities are being given additional duties without the means to deliver Annette Brooke, Liberal Democrats

She said local authorities were equipped to deal with ensuring that there were enough places.

"They'll have to assess the current level of provision, they'll have to listen to the views of parents and others as to what is needed...and act strategically to fill those gaps."

Business advice and start-up funding could be provided by local authorities, although they will not receive any more than the �600 million they already receive.

"Parents will actually be paying for the childcare.

"The local authority will be providing the catalyst for the providers to set up new businesses and provide places," Ms Hughes said.

'Quality learning'

Lib Dem children and families spokeswoman Annette Brooke said: "This Bill, whilst broadly welcome, seems likely to gloss over the many serious challenges the childcare sector faces.

"Reports suggest that new proposals will fail to provide resources for the massive additional costs such as providing more resources to improve care for children with special needs.

"It is vital that the Bill does not force parents back to work, but instead offers parents high quality childcare should they choose to return to the workplace.

"The government must decide whether extending the role of schools amounts to baby sitting or a quality learning experience.