Portland police Sergeant Wayne Nelson said the alarm was raised about 9pm Monday and the rescue ended about midnight with one woman being stretchered to safety.

He said the three 20-year-old Portland women were walking along the cliff top at Cape Grant near the quarry in Portland when they decided to walk down a path to the foreshore.

As the tide rose they became unable to walk back the way they had come down.

They sheltered on a rock and called emergency services on 000.

The rescue coordination centre was contacted and it coordinated a rescue involving Portland police, Portland Country Fire Authority units and State Emergency Service volunteers.

The Victoria Police air wing was about to be deployed but police located the women and SES members assisted with their extraction.

"It all finished about midnight," Sergeant Nelson said.

"One woman was stretchered out. She was suffering shock and exposure symptoms and was

taken to Portland hospital for observation and treatment.

"It was a fantastic result in the end," he said.