The pair have parted ways by mutual consent.
Both men agreed to the decision after Parker's points victory over Junior Fa in Auckland on Saturday night.
"Without Kevin I wouldn't be where I am today," Parker said.
"Together we made it to the very top. Kevin was with me every step of the way, guiding my progress inside and outside of the ring. So it is with genuine sadness that I confirm our partnership has come to an end.
"But the time just feels right. It's fitting that we closed this chapter of my career with a win in front of a great home crowd in Auckland, and with bigger things just on the horizon.
"I know Kevin will always be in my corner."
Parker's tactics and form were heavily criticised following the less than impressive win.
Many fans on social media had been calling for the pair to part ways for some time, and after the Fa fight, both supporters and pundits further questioned whether Barry could take the former WBO champion and further in his career.
The pair have been together for eight years.
"It has been an amazing journey with Joseph and Team Parker. But all journeys must come to an end, and the time is right for myself and Joseph to go in our own directions," Barry said.
"I have been in New Zealand for five months now, away from my family and my other fighters. I have three guys fighting for world titles this year and have responsibilities with them and a few new guys.
"It's not possible for me to stay in New Zealand any longer. For Joe, he has a wife and three young girls in New Zealand, and he wishes to spend more time here.
"I totally understand this and will always be in his corner and support him. We have always had a very close bond and I want nothing but the best for him. We have achieved so much together. It has been one heck of an amazing journey."
In December 2016, Parker became New Zealand's first ever World Heavyweight Champion, defeating Andy Ruiz Junior in Auckland to claim the vacant WBO World Heavyweight Championship.
Parker and Barry managed to secure a unification bout with Briton Anthony Joshua in Cardiff in March 2018.
He would lose that fight and also suffer a defeat to British fighter Dillian Whyte in July the same year, raising questions at the time over his future in the division.
His wins since haven't been of note and he's lacked the knockout finish that fans craved and pundits believed necessary for him to secure bigger fights against the likes of Joshua, Tyson Fury and Deontay Wilder or even a rematch with Whyte.
Fans on social media have largely reacted positively to the news of Parker's and Barry's split, however many have said the decision has come too late to resurrect the New Zealander's career.
Parker could next fight Britain's Derek Chisora, though the bout, expected to be held in London in May, has yet to be confirmed.