'Good Samaritan' carjacker refused bail

A man charged with carjacking and assaulting an elderly couple after helping them with their groceries will remain behind bars while he awaits further court proceedings.

Michael Awad allegedly asked the 81-year-old woman and 90-year-old man for a lift before making off with their car in Sydney's southwest late last year.

The 53-year-old from Bankstown did not apply for bail and it was formally refused by magistrate Rob Rabbidge at Parramatta Local Court on Friday.

Police allege about 12pm on December 13, Awad helped the couple with their groceries at a shopping centre in Casula and asked them for a lift.

While in the car the woman allegedly noticed Awad steal her phone at which point she pulled over and asked him to get out.

Awad allegedly exited the vehicle, assaulted the woman, took over the driver's seat and drove off with the man still inside.

A short time later, police allege he also assaulted the man before pushing him out of the car on Grimson Road, Liverpool, and driving away.

He faces charges of larceny, unlawfully taking or driving a motor vehicle with a person in it, taking or detaining a person with intent to obtain advantage, and aggravated robbery.

Awad is due to appear at Liverpool court on March 9.