Health sector regulator Monitor has announced it will review the closures of NHS walk-in centres.
Monitor said today that it would assess whether the closures were “in the best interests of patients”.
It plans to examine whether the closure of such centres have limited patients’ ability to choose where and when they access care when they do not have an appointment.
Some have linked the crisis in emergency services to the closures.
The NHS Partners Network had asked regulators to investigate it, and Virgin Care, which runs some centres, has also complained about to moves.
Catherine Davies, executive director of co-operation and competition at Monitor, said: “It is in the interests of patients to find out why walk-in centres are closing and whether the closures are affecting patient choice and competition.
“Walk-in centres are very popular with patients and the potential impact of such closures at a local and national level needs to be better understood.”
According to the NHS Choices website, the walk-in centres “have proved to be a successful complementary service to traditional GP and A&E services”.
Some of the high profile closures in recent years include two London-based centres in Tooting and Victoria.
Labour has previously estimated that as many as 40 of the centres, which treat patients with minor illnesses and injuries without them having to make an appointment, have closed since the coalition government took office.
Labour’s shadow health secretary Andy Burnham said: “I welcome that intervention by Monitor.
“We have been saying for some time that it is a false economy to close walk in centres. They have helped take pressure off A&E departments and it makes no sense that so many have been closed in the last two or three years.
“We have estimated that about 40 have been closed since the Coalition came to power.”