Canterbury hospitals will be forced to shut all but acute services next month if health workers go ahead with planned industrial action.

Health chiefs, who have announced plans to indefinitely shut Hillmorton, the region's only psychiatric hospital, yesterday warned a massive shutdown of other hospital services would be unavoidable if they were served with strike notice.

"We can't contingency plan for a month's worth of strikes," said Canterbury District Health Board chief executive Jean O'Callaghan.

"There would have to be a lot of closures - there would be no elective surgery, no outpatient services."

The board has been advised that the combined health unions plan to issue strike notice for next month which would give union members the legal right to strike for three 24-hour periods at a few hours' notice.

Mediation talks with the Nurses' Organisation, which represents 2000 of the 3200 health workers, are scheduled for Wednesday.

In the meantime plans are being made for the closure of all mental health and community health services in Canterbury.

Board clinical director of mental health services Alfred Dell'Ario said the fate of Hillmorton Hospital's 232 patients was still being worked out with the Ministry of Health.

All the district health boards around the country would be surveyed for spare capacity, and it was expected the first patient transfers would begin next week.

The board hopes a settlement can be reached that will avert the strike. Chairman Syd Bradley said it might be able to repackage its wage offer to make it more attractive to the unions.