The State Opposition has labelled a decision to kick a Perth grandmother out of a Department of Housing apartment as 'callous'.

Sue Sinclair's husband died from cancer linked to a government 245T weed spraying program and her son passed away from the same illness earlier this year.

She has now been ordered to vacate her Subiaco apartment because her son was the only person listed as a tenant.

The Opposition Housing Spokesman Fran Logan says Ms Sinclair should be allowed to stay.

"I think this is a shocking case, a case where the department is simply not showing sympathy to a family that has suffered so much already," Mr Logan said.

The Department for Housing has agreed to extend the deadline for Ms Sinclair to leave the apartment.

However the Department's Steve Parry says while it is a sad situation, Ms Sinclair has no right to remain in the property.

"Ms Sinclair has not got a registered application with us and she was not a registered member of the household," Mr Parry said.

"There are in excess of 150 applications for housing in the Subiaco area; some people have been waiting for as long as three years."