Tom Walsh is New Zealand's latest world champion with a gold in the shot put at the World Athletics Championships in London.

A protest by second-placed Joe Kovacs put the title in jeopardy but it was thrown out, confirming a historic gold for 25-year-old Walsh.

The victory means Walsh became the first New Zealand male to claim a medal at the World Athletics Championships with his winning effort of 22.03m coming with his final attempt of the final.

The Rio Olympics bronze medalist joins Dame Valerie Adams (shot put titles 2007, 2009, 2011, 2013) and Beatrice Faumuina (discus in 1997) as New Zealanders to win world titles.

Walsh took the lead with his second attempt of 21.64m and improved on it with his next effort of 21.75m.

But he saved his best until last when the gold medal was already secure, being the only competitor to better 22 metres with his final effort.

Kovacs threw over 22 metres with the penultimate attempt of the competition but he was red-flagged.

Walsh told Radio Sport's Charlie Bristow that the gold medal made up for all the hard work.

"It feels pretty good mate. That's exactly what we came here to do, to win. To do that and to throw so well over the whole comp is something pretty special. It's payback for all the time and effort that the team behind me has put in, and also myself obviously. But without the team behind me, I couldn't have done it."

Amazingly Walsh competed despite a groin injury which meant he wasn't been able to train properly on the eve of the event.

"There's been a lot of treatment in the groin area the last few days," Walsh laughed. "I tweaked it a little bit during the last throw session before it. I was a little iffy how bad it was going to be but it's not that bad is it?".

Kovacs finished in silver with a best of 21.66m with Croatian Stipe Zunic (21.46m) taking bronze. Olympic champions Ryan Crouser was well below his best, finishing sixth with a best of 21.20m.

Fellow Kiwi Jacko Gill finished ninth with a best attempt of 20.82m.