A chubby woman with an accent, possibly Russian, has allegedly tried to entice a schoolgirl to get into her van in Sydney's eastern suburbs.

The girl was standing on the corner of Young and Burge streets in Vaucluse waiting for a lift from a school friend about 9am yesterday, police said.

The woman in the van pulled up alongside the girl, asking her to get in, police said.

The girl declined and phoned her mother from her mobile, at which point the woman drove off.