Mike King is offering a reward for the return of his custom electric bike, which was stolen while he was on a cycling tour of New Zealand to raise awareness for youth climate anxiety.

In a expletive-laden video posted to social media, the entertainer and mental health campaigner said the bike was stolen by “some f***face” outside the Number One Shoes store in Baycourt, Tauranga while he was getting a haircut nearby.

King has been undertaking a nationwide ”I Am Climate Hope” tour.

Mike King is offering a reward for information which could lead to the return of his stolen bike.

“Unbelievable. This is what the world’s coming to,” he said.

“Unf***ing believable, man. As you can tell, I’m p***ed. How the f**k can these fleas get away with this s**t?

“Thieving pricks is all they are. I’d love to get ahold of them and f**king deal to them.”

Towards the end of the video, he said he would give a $500 reward out of his own pocket to anyone who came forward with the address of the thief.

Mike King had taken the custom electric bike over 4700km while on his "I Am Climate Hope" tour of New Zealand.

A spokesperson for I Am Climate Hope said King is “in pain and exhausted” from his journey, and is now without the UBCO bike he has relied on to reach communities across New Zealand.

With increasing numbers of young people expressing mental health struggles tied to the impacts of climate change, King has dedicated this journey to providing support, hope and practical solutions, the spokesperson said.

Mike King is offering a reward for information which could lead to the return of his stolen bike.

Launched on October 1, the tour has seen King travel more than 4850km to engage with communities and address rising youth climate anxiety.

Police are currently investigating the theft, and King’s team has urged anyone with relevant information to come forward.

Updates and photos of the missing bike have been shared on King’s Instagram, along with footage of the individual suspected of taking it.