Catholic schools in Waterloo region will close on Monday if employees go on strike, the school board says.

The Canadian Union of Public Employees (CUPE) represents about 1,100 employees in the Waterloo Catholic District School Board, including adminstrative assistants, early childhood educators, educational assistants, personal support workers, library technicians, payroll and accounting associates and computer technicians.

The employees have already stopped doing some extra work duties.

"In all cases, our school safety and a Christ-centred learning environment remains of paramount importance to us, and our administrators are working diligently to ensure that we are compensating as best we can for the duties not being performed," the board's director of education Loretta Notten said in a statement posted to the board's website.

"Having said that, it is important for all to acknowledge that it is not 'business as usual' across the board, and in some cases compromises have been required, until we are through the job action."

CUPE's Ontario School Board Council of Unions gave notice Wednesday morning it would begin a full strike on Monday if an agreement with the province is not reached over the weekend.

"If the strike proceeds, we will be proceeding to closing our schools commencing Monday Oct. 7," Notten wrote.

Meanwhile, schools with the Waterloo Region District School Board will not be affected because the board said there are no employees who are members of the CUPE bargaining group.

The Upper Grand District School Board says schools will remain open. CUPE local 256 represents custodians and English as a Second Language teachers at 36 elementary schools and nine secondary schools.

French board, Wellington plans

Conseil Scolaire Viamonde — the French-language school board, which has schools in Waterloo, Kitchener and Guelph — says any strike action will impact custodial and maintenance staff at its schools.

"Our administration and educational support staff are represented by a separate union and will not be affected by this action," the board said in a statement.

With custodial and maintenance staff on strike, though, "this could result in cleaning and maintenance duties left unattended on school grounds." The board said other staff members will monitor the cleanliness of schools on a daily basis during any strike action.

The Wellington Catholic District School Board says CUPE represents custodians at schools in Guelph, Rockwood and Erin, as well as system maintenance staff.

"Contingency planning is underway at this time," the board said in a statement.

The board "will continue to monitor the situation through the coming days" and parents and guardians will be provided with updates as more information becomes available.