CBD to be shut down for fatal bus crash re-enactment

A bus crash that killed an 18-year-old woman will be re-enacted in Brisbane's CBD to investigate the cause, with residents urged to avoid the area.

A busy city street will be shut down on the weekend as authorities look at how the tragic event unfolded, with the Brisbane lord mayor on Tuesday ruling out mechanical failure.

Tia Cameron died after a bus mounted a kerb and pinned her against a wall in Brisbane's city centre during peak hour on March 8.

Lord Mayor Adrian Schrinner said the bus had been thoroughly tested and investigations so far determined there was no mechanical fault.

"It was not a mechanical failure, there was no technical failure," he told ABC Radio on Tuesday.

Following the accident, Transport for Brisbane confirmed the bus's brakes had been tested a month before the incident.

Police will close Edward St between Ann Street and Adelaide Street from 7am to 9am on Sunday to carry out the bus crash re-enactment.

Authorities hope it will help them understand exactly what transpired despite extensive video and CCTV footage being reviewed.

"Traffic diversions will be in place as investigators conduct testing at the scene," police said in a statement.

Residents have been urged to avoid the area while the testing is undertaken by police.

Mr Schrinner said the re-enactment showed the police's dedication to provide answers to the family.

"(Police) are now crossing every 'T' and dotting every 'I' to make sure they understand exactly what happened," he said.

Police Commissioner Steve Gollschewski said the re-enactment would be vital for a thorough investigation to help the coroner.

"It is such a tragic event ... (the investigation) is something that has to be done absolutely thoroughly and is really necessary," he told reporters.

The re-enactment may be re-traumatising for loved ones of Ms Cameron but it is important in order to gain answers, Mr Schrinner added.

"Obviously it opens this wound for the community but we have to get to the bottom of it," he said.

"Tia's family deserves to know what happened and there's justice that's required."