Delta Goodrem in tears as The Koi Boys perform Let it Be tribute to Christchurch terrorist attack victims on The Voice

Delta Goodrem was left in tears as The Koi Boys performed Let it Be in tribute to Christchurch terrorist attack victims on The Voice Australia.

The Kiwi singing trio are appearing in an All Stars series of The Voice Australia, that brings back past contestants of the show who came close to winning.

The emotional tribute of the Beatles classic was performed in a Battle showdown against Daniel Shaw.

However, the touching rendition was more of a duet than a battle, leaving many of the judges, including Delta Goodrem, in tears.

In rehearsals, Danny Faifai, Kevin Keepa and Ngahere "Nuz" Ngatai of The Koi Boys talked about why they decided to dedicate the performance to Christchurch terrorist attack victims.

"It's a pretty dark place in the world right now, in light of what's happened back home in New Zealand, an absolute tragedy there in Christchurch," Danny said.

"We were actually there when it happened," Nuz revealed.

"This song, we can dedicate it to the families and the communities that were affected…" started Danny.

"For everyone back home," agreed Kevin.

You can watch the full performance in the YouTube player embedded above.