Childcare experts have raised concerns over plans to stop police being called out to around a third of missing persons cases after the Rochdale sex ring case.
The NSPCC warned changes could put children at risk of being exploited as there is often a link between the two.
The changes are being made following cases such as the Rochdale child sex ring, where nine men were jailed for grooming and abusing vulnerable teenage girls.
We are very concerned that the new definition of 'missing persons' will put vulnerable children at risk of being groomed and sexually exploited.
The length of time a child goes missing is irrelevant because they can fall into the clutches of abusers very quickly.
Children go missing for a variety of reasons - they may be bullied, abused or are generally unhappy. But whatever the reason, this problem must be taken seriously.
We expect all professionals including the police to invest the right amount of time and take the necessary action to protect all children as soon as they go missing."
– David Tucker, head of policy at the NSPCC
A report by the Rochdale Borough Safeguarding Children Board painted a picture of girls as young as 10 being targeted for sexual abuse having been written off by those in authority who said they believed the children were "making their own choices" and "engaging in consensual sexual activity".
Radical measures to transform the way the criminal justice system tackles child sex abuse after Rochdale and Savile cases is agreed.
DPP Keir Starmer QC said what happened in Rochdale has to be dealt with.
Nine men who ran a child sexual exploitation ring in the town were jailed last year. The men from Rochdale and Oldham, who exploited girls as young as 13 were given sentences ranging from four to 19 years.
The men were found guilty of a variety of offences which included rape and conspiracy to engage in sexual activity with a child.
The teenage victims of a grooming ring are considering suing social services. They say their local council failed to protect them. Five girls were abused by the gang in Heywood in Rochdale. Nine men were jailed for a total of 77 in May.