Halifax police say six people arrested Sunday night outside a Canada Post sorting facility in the city's north end have been charged with mischief and obstructing a peace officer.

Police say protesters were posing a "serious public safety threat" and not complying with officers' attempts to disperse them.

Police say they respect a citizen’s right to protest, but traffic was backing up on the dead-end street and public safety was at risk.

“We made attempts with the individuals there to allow them to protest without blocking the roadway without causing a concern for public safety,” said Halifax Regional Police spokesman Const. John MacLeod. “When you start to block traffic, it causes concern for access to emergency vehicles and this is what we found. We found it necessary, after repeated attempts, to have them clear the area to take action.”

The force says it "respects and upholds the right of citizens for peaceful and safe protest," but officers acted in the interest of public safety.

The six people who were charged appeared Monday in Halifax provincial court.

Defence lawyerJoel Pink is representing all six, who were all released on a recognizance to keep the peace, be of good behavior, report back to court as required, and keep away from Canada Post property “except for delivering Christmas cards,” Pink said.

Among those arrested is Tony Tracy, a well-known labour activist.

His wife Suzanne MacNeil was at the protest with him and she says people were there to show solidarity with postal workers recently forced back to work by federal legislation.

“It’s definitely always a concern when police act in this way when workers are trying to make a point and address the rights we are trying to fight for,” MacNeil said.

Canada post has responded by calling Sunday night's protest -- illegal picketing, although no Canada Post workers were involved.

Protesters were rallying outside Canada Post facilities throughout the weekend, after the federal government legislated postal workers back on the job.

Canada Post says it has commitments to customers to ensure mail is being received by all Canadians and are taking all available legal options.

The accused in the case are scheduled to return to court on Jan. 4.

With files from CTV Atlantic’s Natasha Pace.