Charges are likely to be laid against an elderly driver after a cyclist was killed and her husband injured in Sydney's south-east this morning.

Emergency services were called to Pagewood at around 10:00am after the cycling couple were struck by a hatchback being driven by a 79-year-old woman.

Paramedics treated the 35-year-old woman but she died at the scene.

Her husband escaped with relatively minor injuries and is being treated in hospital.

Inspector Andrew Holland from Maroubra police station says it took the elderly woman some time to stop after she collided with the cyclists.

"The vehicle has then travelled another 150 metres before it collided with another vehicle," he said.

"Investigations are making enquiries into her fitness to drive."

The driver has been taken to hospital for mandatory blood and urine tests.