Free flu jabs will be available to everyone in NSW from Wednesday as health authorities warn of a horror winter for influenza.

All West Australian and South Australian residents will also be eligible to receive a free flu vaccination in June. And later this week, Victorian are expected to be told they will be eligible for free shots. In Queensland, free jabs are available until 30 June.

There has been a huge surge in flu infections, with more than 1100 reported cases of respiratory illness in the past week and 150 people attending hospitals.