Rock legends Guns N' Roses apologised Wednesday after confusing the southern city of Melbourne with Sydney on their Australian tour.

Concert-goers booed the US rockers when guitar technician McBob said hello to "Sydney" at the Melbourne Cricket Ground on Tuesday night as he introduced the group on stage.

"Sydney, you wanted the best but they're stuck in traffic, so here's what you get," he said.

The group later tweeted from their official account that they were "truly sorry".

"Melbourne! Accidentally after 30 years McBob made an error, we're truly sorry. Thank you for coming out tonight!"

Lead guitarist Slash apologised on Twitter for the "Spinal Tap intro" while bassist Duff McKagan added: "Don't b2 hard on McBob 4saying 'Sydney' in the intro...his wife and fam r fom here. Hell catch it plenty!"

There has been a long-time rivalry between Sydney and Melbourne, Australia's two largest cities.

While Sydney is the nation's financial centre and boasts of its iconic harbour-front that features the Opera House and bridge, Melbourne prides itself as Australia's cultural and sporting capital.

The veteran band last performed in Melbourne in 2013.