HALIFAX -- A group of unions has banded together to launch a legal challenge against a Nova Scotia law that ended a strike by 2,400 nurses in Halifax in April.

The statement of claim filed Friday in the Nova Scotia Supreme Court alleges the law contravenes the Canadian Charter of Rights and Freedoms and international law by interfering with the right to strike by health and community services employees.

Under the Essential Health and Community Service Act, unions and employers throughout the health care sector are required to have an essential services agreement in place before a strike or lockout and would require an independent third party to decide if such a deal can't be reached.

The statement of claim says Bill 37 also interferes with the right of unions to bargain collectively on behalf of their members and is discriminatory against women.

The claims have not been proven in court.

The province's Justice Department was not immediately available for comment.

The Nova Scotia Federation of Labour, the Nova Scotia Government and General Employees Union, the Canadian Union of Public Employees, the Nova Scotia Nurses Union and Unifor are all part of the court action.