The Sydney Gay & Lesbian Mardi Gras has apologised after it sold over 10,000 tickets to its official afterparty, despite the main venue only having a capacity of 5,500 people.

The post-parade party at the Hordern Pavillion was headlined by Dua Lipa, Sam Smith, Kesha and Pabllo Vittar, with tickets costing between $200 and $270.

Thousands of ticketholders found themselves stuck in the queue when the venue reached capacity, before any performers had even come onstage.

While headline acts had performed in the larger Royal Industries Hall in previous years, that venue is currently under renovation.

Other, smaller venues in the Entertainment Quarter were also part of the afterparty this year, including Max Watts, PJ Gallagher’s and Backyard Burger Bar.

The organisation released a statement on Sunday apologising to ticketholders who were unable to attend the Hordern Pavilion show.

“We are deeply disappointed and apologise that this has occurred,” it said.

“After exploring a range of other options across the city, it was determined the Hordern Pavilion and surrounding areas were still the best venue for the party.

“There just isn’t another inner city space that is big enough for our audience that would allow an all-night dance party.”

Some ticketholders said they were only able to catch the end of the party, while others said they missed out altogether.

One ticketholder who said she visited from Melbourne to attend her first Mardi Gras described the event as “absolute waste of time and money.”

“I DID NOT spend over $200 to wait in a line for hours, not to see a show when you KNEW this would happen, not good enough,” she posted on the Facebook event.

Another attendee complained on the organisation’s Facebook page that the mismanagement caused “much anger and anxiety in patrons.”

“The worst after party experience ever – waited in line for more then 3 hours and couldn’t see any of the main acts – an absolute disgrace, worst organised event I have ever been to,” he wrote.

Other hopefuls Tweeted their frustration from the line.

No word yet if ticketholders who missed out will be given refunds, but it’s clear that people are fuming.

Image: Facebook / Sydney Gay and Lesbian Mardi Gras