A woman has died and nine others have been injured after an 89-year-old man drove into a cafe in Sydney's north-west.

The driver crashed into a table of customers sitting outside Cafe Si:Zac on Malton Road in North Epping about 10:00am.

Liz Albornoz, 39, was taken to Royal North Shore Hospital in a critical condition with serious abdominal injuries but soon died.

Police say the group of women had met to catch up over coffee.

Smashed glass litters the Thai restaurant next door. ( ABC News: Lily Mayers )

Ms Albornoz's mother and husband were "very distraught" a friend told the ABC.

Nine were treated at the scene, with four being taken to hospital in a stable condition.

The driver is at Ryde Hospital for mandatory testing and the crash investigation unit are on scene.

Detective Inspector Mark Christie said the driver was pulling into a parking spot but crashed through a retaining wall.

The car mounted the kerb and struck customers sitting outside the cafe. ( ABC News: Lily Mayers )

Detective Inspector Christie said the situation was "just awful".

"It was obviously a horrendous and chaotic scene," Mr Christie said.

"This appears to be quite a close-knit community, it's just a small local cafe at a local shopping centre. I imagine a lot of people would know each other."

A woman receives medical attention outside the cafe. ( Supplied )

Max Quinnell said his daughter was with the group of women having coffee when the car smashed in.

"She had her back to the car but some of the other ladies saw [the car coming] but couldn't do anything," he said.

Mr Quinnell said his daughter is not injured but "emotionally a mess".

The driver was trying to park when he accelerated into chairs and tables. ( ABC News: Lily Mayers )

NSW Ambulance Superintendent Steve Vaughan said 12 crews attended the "highly emotive" scene.

"People were strewn everywhere … [crews] had to rapidly undertake triage."

Police have asked any other witnesses who have not yet been interviewed to come forward.

The coroner will investigate the woman's death.