New Zealand lock Patrick Tuipulotu tested positive for a banned substance in 2016

All Blacks lock Patrick Tuipulotu tested positive for a banned substance last year, New Zealand Rugby has admitted.

The 24-year-old lock was sent home from New Zealand's end-of-season tour in November 2016 for what was claimed at the time as "personal reasons".

Kiwi media reported on Sunday that Tuipulotu had been provisionally suspended after a positive doping test before the NZR and New Zealand Rugby Players Association confirmed the news in a joint-statement.

It said: "NZR and NZRPA can confirm that, in November 2016, they were notified that a doping control sample provided by Patrick Tuipulotu had, reportedly, revealed the presence of a specified substance listed on WADA's prohibited list.

"Patrick was shocked by the test result and is working hard to identify the source of the specified substance. In accordance with WADA regulations, Patrick remains provisionally suspended pending resolution of this matter.

"Further to these regulations, NZR and NZPRA are bound by strict confidentiality obligations."

Tuipulotu made his All Blacks debut in 2014 and was in contention for the 2015 World Cup squad. but he had to undergo surgery for a congenital hip problem instead and missed most of the season that year.

He returned to the national team in 2016 but returned home early after he played his 12th test in the 68-10 victory over Italy on November 12.