Office workers were left terrified after a Royal Australian Air Force plane flew just metres from high-rise buildings during a major festival.

The Boeing C-17 plane was part of Brisbane's iconic Riverfire at the South Bank parklands.

Footage shows the giant aircraft flying through the city towards the skyscrapers, with one spectator heard calling it '9/11 stuff' as the plane banks upwards at the very last minute to avoid the buildings.

The stunt has been slammed on social media as 'unnecessarily stupid and dangerous'.

The Royal Australian Air Force plane flew scarily close to a cluster of high-rise buildings in Brisbane last month has caused outrage from the public

'All it would take is a small mistake and those buildings and people would be toast,' one person wrote.

'I mean it's cool and stuff, but that could've gone very, very, VERY wrong,' another added.

The Boeing C-17 plane was part of an air show for the Sunsuper Riverfire festival, and footage shows the giant aircraft flying very low through the city

Some people jumped to the RAAF's defence, saying that a great deal of planning would have gone into the execution of the stunt, adding that they wouldn't 'just wing it'.

'Unless both pilots had a synchronised heart attack or catastrophic plane failure, nobody was in any danger,' they wrote.

'I am not saying this is not well thought out,' another responded.

Many online have slammed the stunt as 'unnecessarily stupid and dangerous', asking 'why would they even think that's OK' to fly towards buildings where people live and work

'I am just saying that this could've gone very wrong, very quickly. No need to fly that close to buildings where people live/work etc.'

A Defence spokesperson told Daily Mail Australia that strict safety limits are applied to Defence flypasts.

'An individual flypast plan is developed in advance of each event by Defence aircrew in accordance with Defence procedures and local airspace restrictions,' they said.

'The aircrew involved with the flypast practiced in a simulator beforehand and during a live rehearsal event over Brisbane on September 27.'

Riverfire happens every September in Brisbane to celebrate the end of Queensland's three week arts and cultural festival with a day-long concert as well as aerobatics and flypasts from the Australian Defence Force.