Zambia's ex-president Kenneth Kaunda was on Saturday hospitalised for an undisclosed ailment, forcing a requiem mass for his late wife to be cancelled, an official said.

"The family members have decided that the church service be postponed due to Kenneth Kaunda's sudden illness. Dr Kaunda has... been hospitalised at the University Teaching Hospital," said secretary to the cabinet Roland Msiska in a statement.

Kaunda's wife, Betty, died on Wednesday in Zimbabwe and the government has accorded her three days of national mourning.

The former first lady had been due to be buried on Sunday.