A man came from behind her at about 8.45am, cupped her mouth and grabbed her neck.

She felt a sharp object against her back during the hold-up and handed over her diamond ring worth $2,500, $100 in cash and her mobile phone worth $180.

The assailant then fled in the direction of a nearby private residential area.

He is described as being in his late 20s, skinny and of tanned complexion. He was seen wearing a black cap, dark-coloured jeans and a dark t-shirt. He was also wearing sports shoes.

Anyone with information can call the police hotline on 1800-255-0000.