Police activated a “full emergency response” and roads around Sydney Airport were closed after a United Airlines flight from Los Angeles made a mayday call above the Harbour City on Thursday.

Flight UA839 and its 239 passengers landed safely, despite the pilot reporting a problem on board just after 6:00am.

Authorities said the 787-900 Dreamliner – which was bound for Sydney – was running low on fuel, and the pilot was following procedure.

Airservices Australia said no passengers were at risk during the landing.

NSW Police said major roads around the airport were closed as a precaution just after 6.30am, but reopened shortly afterwards.

-ABC