New Zealand Rugby will confiscate and repair the coveted Ranfurly Shield from recent winners Hawke's Bay after their players broke the trophy.

Pictures posted on social media showed the trophy, also known as the "log o' wood", broken in two, with a caption reading "f*** we broke the ranfurly".

The destruction of the shield occurred during celebrations on Saturday night, after the Hawke's Bay Magpies claimed the trophy with a 20-18 win over Wellington Lions.

Hawke's Bay Rugby Union chief executive Jay Campbell said the trophy was accidentally broken when it was dropped onto a concrete floor.

"No-one is more disappointed than Hawke's Bay Rugby and those involved," Mr Campbell was quoted by Radio NZ as saying.

"It was an absolute accident."

New Zealand Rugby (NZR) had just replaced the old trophy — which was in service for 108 years — with a new one, made from English oak taken from Wellington's Hutt Valley, like the original.

The Ranfurly Shield is a challenge competition fought over by New Zealand's provincial rugby union teams since 1904.

Once a team has taken possession of the log o' wood, it must be won off them in a match in their home province.

Wellington — who won the trophy last year off Hawke's Bay — had held possession for seven challenges, the most successful run in the history of the Ranfurly Shield.

NZR executive Steve Lancaster said the governing body was "deeply disappointed".

"NZR will now take possession of the shield, begin the process of repair and reassess the protocols in place to look after it," he said.

"Our intention is that the Ranfurly Shield remains a part of the community, is enjoyed by those who hold it and cared for as a taonga [treasure] of our game."