The Government's childcare reforms were in chaos after Nick Clegg hit out at plans to relax rules on the number of toddlers nursery staff can supervise.
The Deputy Prime Minister questioned whether the proposals would have the desired effect of reducing costs and said present limits were "already quite a handful" for nursery staff and childminders.
But childcare minister Liz Truss told MPs the system was in desperate need of reform and England had the tightest restrictions in Europe on the number of children each member of staff could supervise.
Under the proposals, from September the ratio for children aged under one had been due to rise from three per adult to four. Each adult would be able to look after six two-year-olds instead of four, but the ratio for three-year-olds would stay at eight or 13 children per adult, depending on whether a qualified graduate was present.
Ms Truss said the Government was considering responses to its consultation on the plans but stressed the need for change. She said: "The current system of childcare is not working for parents. Too many parents in the UK are struggling to juggle their work and childcare arrangements. Families in England pay some of the highest costs in the world - 27% of their income goes on costs, compared to 11% in countries like France."
Ms Truss added: "At present we have the tightest ratios in Europe for children under three and we also have the lowest staff salaries. Nursery staff here earn £6.60 on average, barely above the minimum wage."
The Prime Minister's spokesman said Mr Cameron believed "the right thing to do is to carefully consider all the responses that have been received, to consider the points that have been made and then for the Government to set out its approach".
But Mr Clegg said: "What the Department for Education did is they consulted and they said is it possible to have an adult look after more children, so instead of four two-year-olds ... go up to six two-year-olds? I think four is already quite a handful, just imagine if they go up to six.
"Can you do that at the same time as raising quality? A lot of people basically got back in the consultation and said this isn't going to work, particularly for very small children, it isn't necessarily going to be passed on in terms of cost savings to parents."
Justine Roberts, chief executive and founder of the Mumsnet website, said: "Put simply, parents believe that the quality of care will be adversely affected by the proposed changes and that even with a GCSE in maths and English, four babies under one or six under-twos is a lot for even the most experienced childcare worker to manage."