Coach Tony Brown has been forced to skip Highlanders' Super Rugby Trans-Tasman campaign to help Japan prepare to face the British and Irish Lions, in a situation he conceded on Friday was "not ideal".
Brown has contracts with both the Highlanders and the rugby union in Japan, where he coached the now-defunct Sunwolves and was an assistant with the Brave Blossoms at the 2019 World Cup.
The roles were never supposed to overlap but Brown said rescheduling caused by the pandemic had created a clash that left him unable to fill both roles.
"Having to head to Japan earlier than expected is disappointing particularly leaving my (Highlanders) team before the end of the season, it's not what anyone would have wanted," he said.
The Brave Blossoms play the Lions in Edinburgh on 26 June in a warm-up for the composite team's tour of South Africa.
Brown said Japan's internationals had not spent time together since 2019 and they would undergo a short but intense preparation before heading to Scotland.
The Super Rugby Trans-Tasman competition – which pits Australian and New Zealand clubs against each other for the first time since the pandemic began – runs from 14 May to 19 June.
"The way it has worked out means Brownie's international obligations suddenly overlap with his Super Rugby duties, which obviously is a situation that doesn't sit comfortably with anyone," Highlanders chief executive Roger Clark said.
He said assistant coach Clarke Dermody would take over, with Brown providing regular input remotely.
Brown's contract with the Highlanders runs until the end of next season.