CAPE TOWN - A pregnant mother living in South Africa's Western Cape is being investigated for allegedly murdering three of her children, authorities said on Sunday.

The 36-year-old woman, whose name was not given, has confessed to murdering her two-year-old son, but she might be connected with the deaths of at least two more of her children, Western Cape police said.

"I can confirm we are looking at the deaths of two or more (of her children)," said Warrant Officer November Filander.

The woman, who is due to give birth to another child, confessed to the murder of two-year-old Tariq Jacobs, after being arrested on Saturday.

Jacobs' body was found by members of a community in a shallow grave at a school near Cape Town on Saturday.

An autopsy is being conducted to establish the cause of death.

Police were now also looking into the circumstances around the previous deaths of two or more of her children, Filander said.

The mother is expected to appear in the Mitchells Plain Magistrate's Court on Tuesday on charges of murder and abandonment, according to the South African Press Association.