Maroon 5 frontman Adam Levine has apologised for his "unprofessional" behaviour during a televised festival gig in Chile after facing heavy criticism for his lacklustre performance.

The Moves Like Jagger stars headlined the Vina del Mar event on Thursday night (27Feb20), but audience members were so disappointed with the set - and Levine's apparent attitude during the show - they ended up booing the band off the stage.

The gig, which began 15 minutes late, was broadcast live, and as Levine made his exit, he was overheard complaining, "That was a TV show. That was not a concert."

Viewers were also left less than impressed with the gig and took to Twitter to lash out at the group, with users claiming the singer sounded "awful" as they blasted the "lousy" and "disrespectful" performance.

Levine has since taken to social media to express his sorrow at his behaviour, admitting he struggled with sound issues which impacted his whole demeanour.

"To be totally frank there were some things holding me back last night and I let them get to me," he explained in a video post on his Instagram Story timeline on Friday afternoon. "And it impacted how I was behaving onstage, which is unprofessional and I apologise for that.

"I struggled a lot and sometimes it's really hard for me to mask the struggle. For that, I let you guys down and I apologise."

The rocker went on to insist the group's Friday night show in Santiago would be the best of their South American tour to date.