Police launch urgent search for young man who allegedly sexually assaulted an elderly woman in a lift 

Police are seeking a man they allege sexually assaulted an elderly woman after exposing himself to her in a lift in Melbourne's inner south.

The man, aged in his 20s, is believed to have waited for the woman to enter a lift in South Yarra before exposing himself to her at 2pm on April 1.

He then followed the woman to another floor of the Simmon Street building and sexually assaulted her, before running off.

Victoria Police believe the man is about 180cm tall, with shaved black hair and is perceived to be of Asian descent.

He was last seen wearing a black hooded jumper with the word 'Jordan' written on the back along with black pants and black sneakers.

Police are seeking a man they allege sexually assaulted an elderly woman after exposing himself to her in a lift in Melbourne's inner south.

Police are seeking a man they allege sexually assaulted an elderly woman after exposing himself to her in a lift in Melbourne's inner south.