Dramatic scenes as strong winds cause tree to fall on Sydney tram at Pyrmont trapping 67 passengers

More than 60 passengers were trapped on a tram as strong winds in Sydney caused a tree to fall on overhead powerlines.

Damaging winds sweeping across the state caused chaos shortly before noon on Saturday at Pyrmont, near the middle of Australia's biggest city.

The power had to be switched off before 67 light rail passengers could be safely rescued from the Darling Harbour scene where a fallen tree branch had smashed a glass window.

Strong winds are buffeting New South Wales from near the Victorian border to the mid-north coast, with gale-forced winds of up to 100km/h expected in Sydney this afternoon.

The Bureau of Meteorology has issued a severe weather warning, stretching from Cooma to Kempsey, warning of strong winds continuing into Sunday morning.

The bad weather is set to cause mayhem on highways as families return home, following the end of the state's school holidays. 

Sydney's tram drama could be the start of more work for the state's Fire and Rescue crews, with a spokesman confirming 67 passengers were rescued after the power was switched off.

The Bureau of Meteorology issued an updated on Saturday afternoon, warning of 70km/h average wind speeds picking up to 100km/h.

'Damaging winds are expected to ease during late evening into Sunday morning,' it said.

A weather bureau spokesman said strengthening northwesterly winds were affecting coastal and inland areas.

'A strengthening northwesterly flow ahead of an approaching cold front is bringing vigorous winds to inland and coastal areas,' he said.

'Winds are forecast to shift southwesterly from late afternoon and ease from the west during the late evening into Sunday morning.'

State Emergency Service crews are set to be busy with chainsaws removing fallen trees only a day after a CrowdStrike software update stopped self-serve supermarket checkouts from operating.