'Sparks flew' when powerlines hit GC tram

Passengers say they saw sparks flying when powerlines fell and trapped them inside a Gold Coast tram.

Up to 30 passengers were evacuated from the tram at Surfers Paradise after powerlines broke and fell on carriages about 7.45am.

"I saw sparks flying, heard a bang and then the wire falling down towards the door," a woman told ABC radio.

The operator of the light rail network GoldlinQ says the cause of the powerline break is unknown.

"At this stage we don't know what caused it, but the system kicked in and responded as designed by cutting the power," spokesman Jason Ward said.

"This is the first incident we've had of this nature."

All passengers were helped from the tram safely and suffered no injuries, a Queensland Fire Services spokeswoman said.

Police set up a safety zone, while buses were used to transport affected commuters.

Tram services between Cavill Avenue and Broadbeach South stations remain suspended.

Crews are attempting to repair the line, near the intersection of the Gold Coast Highway and Wharf Street.

It is not known when the network will return to full service.