Cllr Marc Jones, who leads the group, said:
"We were informed by email at 5:30pm tonight that the Executive Board wanted to discuss tomorrow's motion in secret. There is no justification for this - the details of the contract with Kingdom are already in the public domain and have been examined in detail by scrutiny committees that were open to the public.
"Let's be clear, this flies in the face of the huge public interest in this contract. Each year 6,500 people are fined by Kingdom in Wrexham and they and others have every right to hear our argument about why the contract should be ended as soon as possible
"It's up to the 10 members of the Executive Board to decide but we will challenge any attempt to hear this behind closed doors."The Executive Board meets at 10am in Wrexham Guildhall and the meeting is open to the press and public - unless the 10 members decide otherwise.