The bodies of a 24-year-old man and a 22-year-old woman have been found inside a tent at a music festival on Queensland's Southern Downs.

Emergency services were called to the Rabbits Eat Lettuce festival at Elbow Valley, near Warwick, about 9:30am.

Police were treating the deaths as a suspected overdose and said a toxicology report would be completed for the coroner.

The festival, which began in 2008 on the New South Wales mid-north coast, is described as a "tribal Easter party" and a place of "freedom, love and dance music".

The four-day event started on Thursday and wrapped up last night.

The festival's organisers said in a statement they wanted to pass on their condolences to the pair's family and friends.

Festival organisers said it was "heartbreaking to lose some beautiful souls". ( Facebook: Rabbits Eat Lettuce Festival )

"Our thoughts and concerns are predominately for their wellbeing and privacy during this time," the statement said.

"It is truly heartbreaking to lose some beautiful souls that we consider part of our extended family."

The organisers said the wellbeing and safety of patrons was their number one priority.

"We have highly trained first-aid, professional paramedics working 24 hours during throughout the festival and an on-call doctor onsite," the statement said.

"In addition, Queensland Police and Queensland Ambulance are on duty in a user-pay capacity during the festival."

The Rabbits Eat Lettuce organisers last year complained that New South Wales police were charging them $200,000 to attend at different event, called The Bohemian Beatfreaks.

The statement continued: "We work together with authorities to ensure that the environment we provide is as safe as possible. The relevant bodies will be investigating to determine exactly what happened."

It said organisers wanted to "avoid any speculation" over the deaths.

Grazier and B&B owner Andrew O'Dea, who owns the neighbouring property, said there had been a big police presence over the weekend, "with police screening people and drug testing".

"I'm horrified but not surprised, given the kind of activity that goes on there. It's really sad to hear," he said.

"It's pretty awful. It's completely out of character for this area. It is pretty offensive to have people lumped in our backyard."

He said many locals were unhappy with noise and traffic issues.

"It echoes and it doesn't stop. It just goes 24/7 for 72 hours, and that's the main reason why a lot of residents have been unhappy about it," he said.

Festival attendee Jackson Pearson said it was a terrible end to a "brilliant" event.

"It's pretty sad … for festival goers, for their family members, everyone really," he said.

Another festival attendee Camille Lory said she was shocked to hear the news.

"It happens, but it's not like that at every festival, it's still scary," she said.