St George Illawarra front-rower Leeson Ah Mau has officially agreed to join the New Zealand Warriors for the next three seasons, beginning in 2019.

Ah Mau informed the club some weeks ago of his desire to move home to be closer to his family, as the official paperwork was lodged and confirmed by the Warriors on Monday.

The dual international joined the Dragons in 2012 and has made 130 NRL appearances with the club to date.

The 28-year-old was the Dragons' Player of the Year in 2015 and has earnt fan favourite status in his seven years at the club.

"Leeson is a player we tried to retain but we also understood that there were a lot of other implications and they're not always about money," Director of Rugby League Pathways Ian Millward said.

"He's given outstanding service – not only this season, but his previous seasons – and he's been a real benchmark for our other forwards in terms of how he's gone about his business and the way he's played the game. 

"At the end of the day, we're really delighted he's been able to secure a contract. We understand the reasons why he didn't accept our offer and we can't applaud him enough for what he's done for the Dragons.

"We also appreciate that he signalled his intentions early so we have been active in the market place seeking a replacement for Leeson."

Ah Mau said making the decision to leave the Dragons was the toughest he's had to make during his career.

"I love all the boys, the coaching staff and the fans so it was very tough. I had to do what was right for my young family though. Having the support around my wife and daughter was the major factor," he said.

"The Dragons will always hold a special place in my heart. I definitely enjoyed my time here and I'm looking forward to finishing the year on a high.

"I'll miss everyone, especially the fans. They've been wonderful to me over the past seven years and I always love playing in front of them."

Meanwhile, the Dragons have managed to secure the signature Brisbane Broncos Under-20s prop Eddie Blacker on a three-year deal.

Blacker will be an NRL development player upon his arrival in 2019; with promotion to the Top 30 to occur in the years following.

"Quite a number of clubs were in for Eddie, but we were lucky enough to entice him to come here. We bought him and his family down here numerous times to show the pathway we could provide," Millward said.

"He played for Queensland Under-18s last year and is a young man advanced for his age. We were looking for some height and size within the next young powerhouse front-rower to come through the system."