Patrick Koffa's relatives and friends maintained their vigil on Marine Dr yesterday, flanked by well-wishers and members of the Illawarra's refugee community.

In the second day of searching, authorities combed the site from the air, on land and at sea in a dawn to dusk operation.

Veronica Chea, one of Mr Koffa's six siblings, said the 19-year-old's family would wait as long as it took.

"He's part of the family and everybody loves him," Ms Chea said. "The way he died - mysteriously - they just can't believe. We will be here until they find him. We'll keep watching."

Mr Koffa, a TAFE student, vanished while swimming with a group of friends an estimated 200m from Flagstaff Hill about 8.45pm on Sunday night.

Members of the group returned to the water several times after hearing Mr Koffa scream for help, but their rescue efforts were foiled by a strong rip.

Authorities began searching that night.

Yesterday's operation involved Polair, Bendigo Bank Aerial Patrol, State Emergency Service volunteers, Wollongong council jet skis and quad bikes, police divers, Australian Volunteer Coast Guard and Police Rescue.

Authorities are extending the search to cover an area 300 nautical miles off the coast as far south as Kiama.

Mr Koffa escaped war-ravaged Liberia with his family when he was a boy and spent 10 years in a cramped refugee camp in Ghana before coming to Australia three years ago.