Police are asking for assistance to help locate three teenage girls who have been missing since the weekend.

Elisha Nguyen, Jennifer Ly and Julie Le were last seen north-west of Melbourne, on Highfield Road in Cairnlea, at about 4pm on Saturday.

Police and their families hold deep concerns for their welfare due to their age and the length of time they have been missing.

Elisha, 15, has been described as medium build, roughly 152cm tall and wears glasses. She was last seen wearing a red hoodie, jeans and white canvas shoes.

Jennifer, 14, is of slim build with brown eyes and long black hair with blonde streaks. She was wearing a black jacket and jeans with a black purse the last time she was seen.

Julie is also of slim build, 160cm tall, brown eyes and black hair with blonde streaks.

The girls are all described as Asian in appearance and are likely to be together.

Anyone with information is being urged to contact Sunshine Police Station on 9313 3333.