A judicial review will be conducted at the High Court into the use of physical restraint to control children detained in secure training centres.
Campaigners say the restraint rules have become "subjective"
The review will challenge the widening of the circumstances under which children can be restrained.
Campaign group Inquest has argued that the changes, following inquests into two deaths in such centres, were brought in without consultation.
Restraint includes "distraction" techniques, such as a blow to the nose.
The Ministry of Justice changed the rules on restraint following the inquests into the deaths of two teenagers in secure training centres - privately-run detention sites for offenders under 18, contracted out by the Youth Justice Board.
Physical restraint can now be used "for the purpose of ensuring good order and discipline".
Previously the law did not include that phrase, but said restraint could be used to prevent a child escaping from custody; injuring themselves or others; damaging property; or inciting another trainee to do any of the above.
It could only be used "where no alternative method of preventing" those activities was available.
Call for review
An inquest into the death of Adam Rickwood, who was 14, ruled he hanged himself after being restrained while at the Hassockfield Secure Training Centre in County Durham in 2004. He was the youngest person to die in custody in Britain.
Hours before his death, one member of staff restrained the boy with the "nose distraction technique" - an upward blow to the nose.
The technique is a legally sanctioned method of subduing a teenage detainee in extreme circumstances and is designed to shock and stun.
In the other inquest, Gareth Myatt, 15, from Staffordshire, choked to death while being restrained at Rainsbrook Secure Training Centre, near Daventry, Northamptonshire, in 2004.
The coroner in his case, Richard Pollard, subsequently called for a review of physical restraint and control techniques.
Inquest co-ordinator Deborah Coles said the test case at the High Court involved a boy who was released from a secure training centre earlier this year.
If returned to a centre he could be in danger of being physically restrained, she said.
She said the case, on behalf of the child referred to as AC, was being brought because there was a lack of both parliamentary consultation or public debate when the law was changed.
"The change introduced was very subjective in nature.
"Previously the criteria for physically restraining a child was very narrowly defined, but the rule change has made it very subjective.
"There was a lack of any intense scrutiny that this kind of change should have been subjected to," Ms Coles said.
In July the government announced an independent review of the policy and practice on the use of restraint in juvenile secure units, including secure training centres, secure children's homes and young offender institutions.
The recommendations of this review are expected in April 2008.