Speaking to The Tab, eyewitness Rosie explained how a group of boys joined the queue and began pushing, she says this led to the barrier falling over.
Doormen desperately tried to resuscitate her and paramedics arrived to give emergency treatment, but she sadly died at the scene.
Detective Superintendent Kevin Weir, from Durham Constabulary, said: 'This was a tragic incident and our thoughts are with the family and friends of Olivia during this incredibly sad time.
She reportedly became trapped under a fence as students queued to get into Missoula nightclub in Walkergate on Wednesday night.
A Durham Police spokeswoman said: "The circumstances surrounding her death are unclear at this time".
The nightclub has been contacted for comment.
They added: "The 20-year-old Durham University student died in the vicinity of Missoula night club in Durham following an incident at about 11:55pm last night".
Olivia sustained fatal head injuries while queuing to enter Missoula club at 11.50pm on Wednesday Night.
Forensic experts were conducting a search of the scene yesterday as police launched a probe amid claims the tragedy happened after a group of male students pushed from the rear of the crowd.
Burt, a member of the British sailing team, was described by Durham as an "exceptional sportswoman" and a "bright and outstandingly able student", as her friends spoke of the loss of a "wonderful girl".
In a number of heartbreaking tributes posted on social media, friends describe the student as "a bright, lovely and kind person". "It is hard to come to terms with her loss, and we will miss her greatly".
"Olivia's passion for sailing always shone through and all those who knew her in the sailing community will miss her tremendously; she was both a likeable and fair competitor", he said. People were trying to reason with them, telling the bouncers it wasn't safe and someone was going to get hurt.
"You will appreciate that I am unable to share further details given the ongoing Police investigation".
A spokesperson for Durham Police today said they have launched an investigation.
A large floral tribute was placed outside Missoula, formerly a Slug and Lettuce pub, which opened in September 2016 after a £385,000 investment.
'Our thoughts are with the young lady's family and friends'.