Elton John in tears as he's forced to cut NZ show

An emotional Elton John had to cut short a performance in New Zealand on Sunday after he lost his voice due to walking pneumonia and had to be assisted off stage.

John reached out to his fans on Instagram on Sunday, apologising for ending his show at Auckland's Mt Smart Stadium early.

Video clips posted online by fans who were at the performance showed John breaking down in tears as he told the cheering crowd that he could not go on any longer.

The New Zealand Herald reported that John, 72, told his fans earlier that he had walking pneumonia and his voice was shot, but that he didn't want to miss the show.

At one point, after performing "Someone Saved My Life Tonight," John slumped on his stool and required medical attention, the newspaper reported.

But John recovered and continued to play.

Later, as he he attempted to sing “Daniel,” he realised he had no voice left and was escorted off stage.

The concert was part of John's Farewell Yellow Brick Road tour.

The tour lists additional performances at Auckland's Mt Smart Stadium on Tuesday and Thursday; there's no word on whether those shows will go on as scheduled.

According to the Mayo Clinic, walking pneumonia is an informal term for a milder form of pneumonia that isn't severe enough to require hospitalisation or bed rest.

It affects the respiratory tract and is most often caused by bacteria.