Jodi Henrickson was last seen at a house party on June 20 on Bowen Island. (Facebook)

Police, aided by search and rescue volunteers, continued their search on Wednesday for a teenage girl who has been missing for 11 days.

Jodi Henrickson, 17, of Squamish, was last seen around dawn on Bowen Island after attending several house parties on June 20. Four days later, her parents reported her missing when she failed to come home.

"Investigators are still of the belief she's still on the island," Squamish RCMP Cpl. Dave Ritchie said Wednesday.

Police say they are investigating several tips, including reports of sightings as far away as Calgary.

One of the last people who may have seen Henrickson is Gavin Arnott, 20, a former boyfriend.

According to court documents, Arnott was convicted of assaulting Henrickson on April 8. The Bowen Island resident was sentenced June 5 to 18 months' probation, and one of the conditions was that he have no contact with Henrickson.

Arnott "was on Bowen Island the night of the 19th into the 20th and was seen with Jodi," Ritchie said, confirming that Arnott had broken the conditions of his probation.

While a police helicopter swept the island on Wednesday, about a dozen search and rescue volunteers from the North Shore, Lions Bay and Coquitlam continued their search in the Eagle Cliff area.

"It's not difficult terrain at all," said Tim Jones of North Shore Search and Rescue. "It's mainly in the residential area and teams are going in just to check the properties."

Police said they would continue searching until early evening and then assess what measure to take on Thursday.