Track work on the T4 Illawarra line will cause delays for people heading into the city to try out Sydney's new light rail system, which opens tomorrow (Saturday).
The first disruption will occur from 9.50pm on Friday when buses replace trains between Cronulla and Sutherland.
This will allow further work on the Gannons Road, Caringbah rail bridge, which will also see the closure of the road underpass for the weekend.
From 2am Saturday until 2am Monday, buses will replace trains between Cronulla, Waterfall and Central.
The first light rail passenger service will start at 11am on Saturday and run between Circular Quay and Randwick.
Passengers will travel free on the first weekend.
"This first weekend of passenger services will be busy so expect queues and bring sun protection and water," a Transport for NSW statement said.
"Based on other opening events, the busiest times over the weekend are likely to be around the middle of the day, so plan ahead and try to avoid busier times in the late morning and lunchtime period.
"The new network will move up to 13,500 commuters an hour during peak time in both directions, replacing the line of buses which used to sit in traffic on George Street.
"A coupled tram holds up to 450 customers, the equivalent of up to nine standard buses.
"On weekdays, frequent services will run approximately every four to eight minutes between Circular Quay and Central, and every eight to twelve minutes between Central and Randwick, from 7am to 7pm as services are bedded in over the next six months.
"Services on the CBD and South East Light Rail will run from 5am to 1am every day of the week.
"With passenger services right around the corner it's more important than ever for the community to pay attention to safety messages around trams.
"The Heads Up! Play It Safe Around Light Rail campaign is educating the community about ditching distraction and making sure drivers stay out of the tram corridor and don't queue across intersections."
