Around 150,000 people have flocked to Sydney Olympic Park for a variety of events in numbers thought to be the biggest seen since the Sydney Olympics in 2000.
Singer Taylor Swift was due to play to a sold out ANZ Stadium in the first Australian show of her 1989 World Tour, while tens of thousands of others revelled in international DJs and producers like Diplo and DJ Snake at the Stereosonic electronic music festival.
Also in the precinct, is motocross event the Aus-X Open and the Australian Short Course Swimming Championships.
Punters - many sporting themed costumes - began to stream in from early in the afternoon, creating bottlenecks for traffic in the area and causing "significant delays".
Shortly before Shake It Off singer Swift was due to take to the stage in the evening, traffic was operating as normal, but police anticipated heavy traffic for some hours after the events ended in areas including the M4 Motorway, Homebush Bay Drive and Parramatta Road
At least one person was pinned down by multiple police and arrested as they tried to enter the Stereosonic festival, but police weren't able to provide figures on arrests and drug seizures until after the event ended.
The precinct went into "lockdown" this week and was subject to regular "sweeps" by police and drug dogs to stop people from hiding drugs in the venue and picking them up once the festival was in full swing.
Two people were allegedly caught trying to hide drugs in the area, including one man who allegedly drilled a hole in a building to try to stash drugs there.
Ahead of the event, NSW Police Assistant Commissioner Frank Mennilli said a "high-visibility" police operation would be in place in the area on Saturday.
"We're focused on maintaining a family-friendly environment in the precinct, and while we want everyone to have a great time – anti-social behaviour will not be tolerated," Assistant Commissioner Mennilli said.
"We're also urging everyone to 'think before you drink.' For everyone's safety know your limits, and don't take risks that may lead to you becoming a victim of crime, or an offender."
Officers patrolling Strathfield Station as part of the high-visibility police presence were allegedly attacked, with two police taken to hospital, after they spoke to an "anti-social" crowd.
Trains will leave Olympic Park Station for Central Station every four minutes after the events conclude.
