Mark Hammett's tenure at the helm of the Cardiff Blues has ended just six months into a three year contract.
The former Hurricanes coach has endured a tough time in Wales, with his side winning just four of 15 matches since taking the job.
The club insists Hammett has not been sacked, but is leaving for personal reasons with his mum not very well.
In a statement, the Board of Directors at Cardiff Blues said it was disappointed at the move but had been accepted.
Richard Holland, Chief Executive at Cardiff Blues, said: "We were naturally very disappointed and surprised when Mark informed us of his decision. However, we fully understand the personal reasons he has given and he has our full support.
"We appointed Mark last summer as part of a long-term vision for Cardiff Blues. He has worked tirelessly in the role since his arrival in Wales and we always felt Mark was the right man to take us forward, right up until his decision to leave.
"Mark has made a number of positive changes that will benefit our region for years to come. He leaves us in a stronger position than when he arrived and I'd like to thank him for his contribution during this season.
"Having spoken to Mark at length, I know he's not taken this decision lightly. However he feels he must return to New Zealand. We fully respect the decision he has made with his family and, on behalf of all the staff at Cardiff Blues, I wish them every success in the future."
A poll on WalesOnline, one of the leading websites in Wales, has 70% of respondents sad to see Mark Hammett exiting the Cardiff Blues.
The site pointed out that under Hammett the Blues had won just four of their 15 Pro 12 matches this season making them the lowest ranked Welsh team in the table.
The site claimed that the team found out about Hammett's departure just hours before they played against another Pro12 team, Treviso in Italy. The players were said to have been blindsided when the news started circulating on social media and they went on to suffer a humiliating 40-24 loss to the lowly Treviso.
The site also named former Kiwi Shane Howarth as one of the possible replacements for Hammett, as well as Jamie Joseph.
In his statement Hammett said: "It was always my intention to bring success to the region over the full length of my contract.
"However, I must put my family first and therefore it is with regret that I am leaving the role.
"I'd like thank [backer] Peter Thomas and the board of directors for their support in allowing me to return home as soon as possible.
The UK's Rugby Paper noted that a poor campaign by the Blues had led to pressure on Hammett to resign.