VANCOUVER -- Lawyers for the Insurance Corporation of B.C. have argued that employees who have altered the company's email signature as part of a labour dispute could be considered to be pressuring clients into supporting the union to have their claims adjusted fairly.

ICBC was in B.C Supreme Court Friday asking for an injunction that would stop more than 1,000 employees from sending out emails with an unauthorized pro-union message.

As part of an ongoing job action, the employees changed the bottom line in their work account emails to messages such as "We work, you drive; we both deserve better."

Almost 20,000 emails have been sent with that sort of sentiment, and the corporation's lawyers argue the tactic has hurt the insurer's brand.

ICBC lawyer Geoffrey Litherland told the hearing in Vancouver employees were sticking words into the corporation's mouth.

"This is not a job action the way a lockout or strike would be. It is more of an attempt to garner sympathy for the cause," he said.

"Freedom of expression does not include union rights over employer's property."

But a lawyer for the union contends the case should be dealt with by the Labour Relations Board, because the messages are a form of union job action.

Jessica Burke, who represents the Canadian Office and Professional Employees Union local 378, told court the email signatures are no different than picketing or leafleting.

"(The case) clearly arises out of the employer-employee relationship, which is governed by the collective agreement," she said.

The union also argued ICBC has no proof its members are confusing clients or making them feel pressured to support the union, calling the suggestion "speculation."

A judge reserved his judgment on the matter.

The union and ICBC have been trying to reach a new collective agreement since 2010.

Union members passed a strike vote with 87 per cent support last month, but B.C.'s labour board ruled they couldn't stage a full-scale walkout.

The union has responded by devising other ways of exerting pressure, including banning overtime and company training, and threatening to prevent the delivery of provincial health cards come the fall.

The Labour Relations Board ruled earlier this month that ICBC was not bargaining in good faith.