Gunman on bike robs two women in Sydney

Two women have been robbed at gun point south of Sydney by a man on a mountain bike.

The pair, aged 18 and 19, were walking in Zetland about 9pm on Monday when they were confronted.

The man brandished a small black handgun and demanded their bags and mobile phones before riding away.

NSW Police believe the robber was aged in his mid to late 20s, unshaven and wore a grey beanie and a dark T-shirt and jacket.