VANCOUVER -- The contract dispute between British Columbia's teachers and the province continues to escalate, with government negotiators responding to the teachers' strike plans with a partial lockout and each side accusing the other of dragging students into messy negotiations.

The teachers and their employer offered dramatically different assessments of what precisely the tit-for-tat will mean for students in their final month before summer break.

The union painted a dire picture of exams left unmarked, student activities cancelled and graduation ceremonies in jeopardy -- all laid at the feet of Liberal Premier Christy Clark.

In contrast, the B.C. Public School Employers' Association, which bargains on behalf of the government and its school boards, said the only thing that will be significantly affected is teachers' pay. The group promised after-school activities and grad celebrations won't be touched.

The developments come in the middle of negotiations that have been particularly nasty, even when compared with the B.C. government's already troubled relationship with its teachers, which has been mired by strikes and back-to-work legislation since the 1990s.

The union announced earlier this week that rotating, one-day strikes would target all public schools in the province beginning Monday. The strikes will last four days, with every school closed for one of those days.

The employers' association responded by announcing a partial lockout, which includes a 10 per cent pay cut if teachers follow through with their plans to walk off the job.

The lockout will also restrict the amount of time teachers will be permitted to be at work and, if a deal isn't reached by the end of June, force high school teachers to stay home for three days and elementary teachers to be off work for one day.

Jim Iker of the BC Teachers' Federation described the lockout as an attack on teachers. He branded the measure "Christy Clark's lockout" and urged parents to blame the premier if activities and graduation ceremonies are cancelled.

"The premier, who once promised to put families first and who just (Wednesday) said that children should not be put in the middle, is launching significant disruptions to our education system," Iker told a news conference Thursday at the union's offices in Vancouver.

"This government is so desperate to attack teachers that it is putting student academics and extracurricular activities at risk."

However, Peter Cameron, the lead negotiator for the government, accused the union of spreading falsehoods.

Cameron said school boards have no intention of preventing teachers from volunteering on after-school activities, supervising field trips or attending grad celebrations, and he said the terms of the lockout will be "tweaked" to ensure that is clear.

Rather, he said the goal is to put pressure on teachers by targeting their paycheques. The union, not the government, is hurting students, he said.

"They're trying to obscure the issue that they're shutting the school system down (with next week's rotating strikes) and interfering with instruction," Cameron told reporters in Vancouver.

"We think we've designed this response to be absolutely minimal in terms of its impact on students, but if there is some unanticipated thing ... it'll be tweaked and it will be organized."

The teachers' union noted students in Grade 10 English and Grade 11 social studies write their final exams on June 24. The full-scale lockout begins the following day, which means teachers won't be at school marking exams, the union said.

Cameron said the terms of the lockout will be adjusted to ensure those exams are marked.

Teachers want higher wages along with commitments to make classes smaller and increase the number of specialists in schools -- which the province has warned would cost hundreds of millions, if not billions, of dollars.

The latest government wage offer added up to 6.5 per cent over six years, followed by indexed increases. It also included a $1,200 signing bonus, which remains on the table.

The province said teachers are asking for a pay raise of 15.9 per cent over four years, but with increased benefits and other provisions, the total would be about 21 per cent.

Union members voted 89 per cent in favour of striking in March. Teachers have already stopped supervising students outside the classroom or communicating in writing to administrators.