Two women have been charged after a frail 86-year-old pensioner was bashed and robbed in the underground car park of a western Sydney shopping centre in an attack police have described as "cowardly".

The women were arrested hours after Frank Carlino, who uses a walking stick, was robbed of the pension money he had just withdrawn from a bank in Chester Hill about 9.45am on Wednesday.

Two women have been arrested after an 86-year-old man was attacked in a car park. Credit:Channel Nine

Police are still searching for a man, thought to be aged in his mid 30s, who is also wanted over the attack.

CCTV footage from the car park at Chester Square shopping centre, and obtained by Channel Nine, shows Mr Carlino being stalked through the car park before he is punched in the face by a man, as a woman keeps a look out.