VANCOUVER -- The intensifying battle between British Columbia's public teachers and their employer moved to a provincial labour tribunal Thursday where the employer defended the right to chop 10 per cent of teachers' pay while the union demand a cease and desist order.

A lawyer for the B.C. Public School Employers' Association, on behalf of the government, asked the Labour Relations Board to rule that lockout provisions including the pay cut and a limit to teachers' hours of work could continue during the union's rotating strike.

Eric Harris argued during a day-long hearing that the employer is entitled to refuse teachers' pay if they're not doing their job.

"Our view is the matter is extremely simple," Harris told the tribunal adjudicator. "We are within our rights under the (labour) code."

A lawyer for the B.C. Teachers' Federation vigorously objected, telling the board the employer was making a "unilateral" cut without merit.

"The employer is being arbitrary. Frankly, they're just making it up in terms of their 10 per cent figure," Carmela Allevato said.

"(The employer) again seems to be pursuing an agenda in order to provoke teachers into an all out strike."

The hearing comes during an escalating dispute between the union representing more than 40,000 teachers and the employers' association, which also represents provincial school boards.

The BCTF is disputing lockout provisions the employer has imposed since Monday, when teachers across the province began rotating strikes at schools across the province.

Harris told the board that teachers shouldn't expect 100 per cent of their pay when they're no longer fulfilling all their duties.

"BCPSEA has the right to lock out in these circumstances," he said. "We have not caused an amendment to the collective agreement."

The 10 per cent pay cut is significantly less than the percentage the union itself calculated for time worked, Harris noted. He said the issue should not be handled by the board, but instead moved before an arbitrator.

Allevato said the employer's refusal to pay effectively alters the collective agreement, based on "a blanket determination" around teachers' workload. The contract provides that teachers are paid an annual salary, she said, meaning that any formula using quantity of time worked as rationale for deducting wages should not stand.

Confusion abounds during the dispute, owing to a wide array of interpretations of the lockout, she added.

Allevato cited a situation on northern Vancouver Island where teachers who received paycheques this week were not only docked 10 per cent pay for the current week of rotating strikes but also retroactively for last week.

The board adjudicator said he'd attempt to deliver a ruling next Wednesday.

Outside the hearing, Michael Marchbank, BCPSEA public administrator, explained the 10 per cent deduction was calculated by looking at the difference between what duties teachers normally perform and what activities they've halted.

"We think the 10 per cent is a conservative number," he said.

Marchbank said if the teachers cease their strike action, the employer will end the lockout and reinstate pay.

On Wednesday, the union announced it will continue rotating strike action for another four days next week. Up to 150,000 students will be off school for one day each in various school districts on either Monday, Tuesday, Thursday or Friday.

The escalating job action has had the union and Education Minister Peter Fassbender accusing each other of refusing to move from their bargaining positions.

Wages and class size, along with support for students needing learning assistance, are the major issues involved.

The government is offering a wage increase of 7.3 per cent over six years, while the union wants a 13.7 per cent raise over four years.