Blues lock Kurtis Haiu, who passed his milestone 50th game for the side this season, is on indefinite leave after a tumour was found on his rib.

"This appears to be a primary bone tumour but he will have to undergo a series of further tests, including surgery, to definitively confirm the type of tumour," team doctor Stephen Kara explained. "Until this time, prognosis is uncertain."

Tests discovered the lesion on 26-year-old Haiu's rib late last week. A few in the coaching staff and captain Keven Mealamu were told after the Blues' latest win against the Rebels, and Haiu spoke to the squad in an emotional meeting on Easter Monday.

"It is treatable. The first instance will be removing the cancer and part of the rib and then any additional therapy - that's dictated by what the results of the testing show," Kara said.

Haiu had suffered intermittent pain for a few months but attributed that to the contact work in rugby. About a month ago, the increase in levels and frequency of his pain led to more specialist investigation, including blood tests and x-rays.

Kara received the disconcerting results and, with coach Pat Lam, had a meeting with Haiu last week.

"It's quite devastating and tragic for him and his family," Kara said.

Haiu is to see a bone tumour specialist next week.

"It's probably the hardest thing to do as a coach, to go round to one of your players and give that sort of news. Kurtis has two young girls and his wife was there as well," Lam added.

The young lock attended the Blues game on Good Friday and afterwards told Lam he wanted to give his teammates the news on Monday.

"Just before lunch on Monday, Kurtis came in and shared the news with the boys and it's fair to say it was an emotional time for the team. The biggest thing for us is we go out to battles all the time, and rugby is a great team sport where you rely on the guys next to you and that's pretty much what we conveyed to him," Lam said.

Haiu has played 75 games for Auckland and 53 games for the Blues since his 2006 debut.