Party leader Geoff Simmons made the announcement this morning.
"It seems that politics is too similar to herding cats for his liking, and he can't wait to sink his claws into his many other interests," Simmons said in a statement.
At the 2017 election, The Opportunities Party secured 2.4 per cent of the party vote.
"Dr Morgan started the party in 2016 to contest the 2017 election. His no-nonsense style and innovative, well-researched policy attracted followers from all ages," Simmons said.
The party still planned to contest the 2020 election.
Morgan has poured an estimated $2 million into the party to contest the 2017 election.
His comments have courted controversy including referring to Prime Minister Jacinda Ardern as "lipstick on a pig", telling TOP candidate Dr Jenny Condie she was a "pain in the arse" and should quit the party in an email to all party members, and being critical over the lack of a cat fence as others offered sympathy when Ardern's cat Paddles was run over.
Morgan quit as TOP leader after the 2017 election, but stayed on in the policy team.
Last year the party's board decided to deregister, but that was later reversed.
Simmons won a leadership contest at the end of last year, despite Morgan backing his rival Amy Stevens.
"The Opportunities Party is now truly a movement and will contest the 2020 election as a broad-based, member-led party. We will always be grateful to Dr Morgan for the initial momentum he provided," Simmons said.
"Some early policies have now moved into the mainstream, largely due to Dr Morgan's influence, but there are plenty of thorny issues that need fresh, future thinking.
"New Zealand needs The Opportunities Party at the parliamentary table to address the larger, longer-term problems that most career politicians will not address."
He thanked Morgan for creating the party and said TOP would honour his legacy by "discarding irrelevant, outdated notions of political ideology and focussing on 'Not left, not right - just doing what works'."
TOP has about 4200 core members and over 30,000 followers on social media, he said.
