Videos posted to social media show stretching queues of people trying to access the city for the popular event.

The drone show has proved a hit with crowds flocking to the harbour to see the spectacle unfold above Circular Quay.

There are only two left, on June 12 and June 14, with large crowds expected.

Attendees are being advised to plan ahead with service changes on the night of the drone shows.

"Measures are in place to ensure everyone can enjoy the drone shows safely, and from many vantage points around Sydney Harbour," an event statement said.

"Stay up to date with the latest travel updates from Transport NSW and you can find further information on travelling to Vivid Sydney in our Trip Planning Guide.

"The Vivid Sydney drone show will also be live streamed on Vivid Sydney channels on June 12."

IN OTHER NEWS:

Transport NSW is also forecasting big crowds at the event on the King's Birthday long weekend.

"Don't drive. Roads will be closed, traffic will be extremely busy, and parking is very limited. Plan your trip on public transport instead," a Facebook post from Live Traffic NSW said.

Police will be out in force as motorists hit the road for the long weekend.

Double demerit points are in place in NSW and the ACT from June 9 to June 12.

NSW Police is targeting speeding, mobile phone, seatbelt and motorcycle helmet offences.

Meanwhile, Victorians can also get a taste of a winter festival on the long weekend with Rising taking over the city from June 7 to 18.

Extra public transport services will run on June 10 as trance fans flock to the Subculture Festival at the Melbourne Showgrounds.