Northern Illawarra residents are again being forced south for medical treatment, with Bulli Hospital's emergency department all but closed until next week.South Eastern Sydney Illawarra Health is urging people with non-urgent medical needs to go straight to Wollongong Hospital.Those who turn up at Bulli Hospital's emergency department will be seen by a nurse, but only those seriously ill will be transferred by ambulance to Wollongong Hospital.Less serious patients will be asked to make their own way. The arrangement will be in place until at least Monday night.The health service, addressing community concerns the measure was an indication the hospital would be permanently closed, reaffirmed a recent pledge to keep it open.Southern network manager Sue Browbank said the diversion strategy was needed to help cope with an increase in emergency department presentations across the region's hospitals - and a shortage of doctors.Several doctors had called in this week with the flu. "We've been having some difficulties (in replacing the sick doctors) because there is a nationwide shortage of locum doctors," Ms Browbank said.The shortage of locum doctors generally worsened during winter, when doctors become ill, and this year was worse than usual because of the swine flu, she said."We are being particularly cautious with our staff, encouraging them to stay away if they have the flu."Increased pressure on Wollongong Hospital's emergency department has already been felt this winter, with ambulances regularly forced to wait hours to offload patients. Ms Browbank said the situation could worsen during the school holidays.Extra beds would be opened gradually, but in the wake of the swine flu outbreak Ms Browbank urged people with flu-like symptoms to visit their general practitioner or the flu clinic at Wollongong Hospital, rather than the emergency department.People with non-urgent medical needs can phone NSW Health Direct and speak to a registered nurse on 1800 022 222. Unwell visitors are being urged to stay away from hospitals.