Minister Nathi Mthethwa consulted legal practitioners in the field of constitutional law who found that the Bill was not constitutional "in its entirety", said spokesman Zweli Mnisi in a statement.

Mthethwa also instructed the civilian secretariat for police to make submissions on the draft Bill.

The proposed legislation would grant the province powers to monitor the police and foster co-operation between the police and communities.

It also provided for the appointment of a provincial police ombudsman.

Under the Constitution, the national commissioner of police is tasked with the control and management of the police service.

Mnisi said Mthethwa had raised his concerns with community safety MEC Dan Plato.

"Should the Bill go ahead the Minister has informed the MEC that the Ministry will challenge the constitutionality of the Bill."

Plato said he would comment on the matter later on Tuesday.