Melbourne airport clearing flight backlog

Melbourne Airport is clearing a backlog of flights after technical issues at Sydney Airport sparked air-travel chaos at major terminals across the nation.

The Melbourne to Sydney route is open but passengers should expect delays throughout Monday, a Melbourne Airport spokeswoman told AAP.

Sydney's terminal was hit by radar failures at about 5am, which also resulted in flight delays for thousands of air travellers south of the NSW border.

The issue sparked a "domino effect" in Melbourne, the spokeswoman said.

Melbourne passengers have been advised to check for delays with their airline.

The disruption comes on the first day of Victorian school holidays.