A promoter behind Lady Gaga's tour has explained the star's lackluster performance in New Zealand which sparked fears for her health - insisting the singer was "tired and dehydrated."

The Poker Face hit-maker was hit with reports of a health scare after a video from her gig in Auckland over the weekend showed her looking woozy and fatigued.

The singer was seen half-heartedly joining in the dance routine to her hit Bad Romance, before stripping off her headgear and lying down on the stage.

A promoter behind her Monster Ball tour has now put Gaga's worrying antics down to tiredness and the searing heat in the Vector Arena, insisting the singer will be fully fit for upcoming concerts in Australia.

Tour promoter Michael Coppel says, "(Lady Gaga is) totally fine. It was warm at the show, she was tired and (a) bit dehydrated by the end of a two-hour plus performance. She performed the second Auckland show the following night without an issue and will be back in full match fitness for her first Australian show."

Gaga cancelled a series of concerts in the U.S. in January after suffering from exhaustion.

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