A survey of 570 schools in three areas of England found 96 were in breach of the statutory admissions code, Children's Secretary Ed Balls said.

In six cases, schools asked parents to promise to make "voluntary" financial contributions as a condition of entry, he said.

Mr Balls said 29 schools in the survey covering Manchester, Northamptonshire and the London Borough of Barnet failed to comply with at least two requirements of the admissions code.

He stressed that the vast majority of schools surveyed were keeping to the rules but warned that there was no reason to think that the picture would be different elsewhere in England.

Most of the schools found to be breaking the rules were faith schools which have control over their own admissions.

Mr Balls said one Jewish school in Barnet wanted parents to pay £895 per child per term, while another was asking for £670 per term.

Mr Balls said the schools breaking the rules failed to comply with a range of different legal requirements.

He said 58 failed to give children in care the highest priority for places while 13 had tended to have a say over whether they admit children with special needs.

Measures will be brought in to force local councils to report on the fairness of school admissions in their areas and to make it easier for the independent schools adjudicator to investigate concerns, he said.