Ryan Cleary says his jaw-dropping decision to defect to Newfoundland and Labrador's Progressive Conservatives was motivated by his fears that the Liberals might form a stranglehold on governments at the federal and provincial levels.

"That kept me awake at night," Cleary said during a news conference Friday in St. John's, during which he announced his intentions to seek the PC nomination in Windsor Lake.

Cleary​, who was defeated just last week as a New Democratic MP, admitted that his relationship with the provincial NDP and its leader, Earle McCurdy, was frosty.

What voters think of Ryan Cleary's move to PCs 1:01

He also suggested it may be time for a "separation" between the provincial and federal NDP.

As for his many supporters, Cleary said he is still the same person, with the same values and principles.

"I hope they support me still," he said.

Poised for election showdown with Cathy Bennett

Cleary said he believes a PC government, led by Premier Paul Davis, is the best way to ensure that the promises made by the federal Liberals during the recent campaign are kept.

With the Liberals sweeping every seat in Atlantic Canada, including the seven in Newfoundland and Labrador, Cleary said having Dwight Ball and the provincial Liberals win on Nov. 30 would be a "political worst-case scenario."

"A PC government would ensure the best interests of Newfoundland and Labrador are looked after always, and I can make sure of that," Cleary said.

Premier Paul Davis welcomed Ryan Cleary to his team Friday as the governing Tories prepare for the Nov. 30 Newfoundland and Labrador (CBC)

If he wins the nomination, Cleary will square off against high-profile Liberal MHA Cathy Bennett.

The Liberals have been polling strongly in recent years, and are favoured to win next month's election.

Cleary said he wants to help stop that momentum.

"Majorities in Ottawa and right here in Newfoundland and Labrador would not work for democracy, and would not be in our best interest," Cleary said.

Called to the premier's office

Cleary said his election loss in St. John's South-Mount Pearl gave him the "freedom" to think about his political future, and that included talks with both the provincial NDP and the PCs.

He said he became friends with Davis during the dispute with outgoing Prime Minister Stephen Harper and the Conservatives over minimum fish processing requirements, and a fisheries innovation fund related to the a trade deal with the European Union.

He said the "premier asked to see me in his office" and "that has led to where we are right here today."

Planted trees in Windsor Lake

Cleary said it was not an easy decision, but noted "change is good, even for me."

As for his decision to run in Windsor Lake, Cleary said his attachment to the district is quite deep.

He said he raised his two boys in the district, played street hockey on Parliament Place, and "planted trees and watched them take root."

"I know the district, the people," he said.

Ryan Cleary's Facebook page on Friday morning still featured a photo that showcased his political career with the NDP. (CBC)

Davis and many top PC party officials were on hand for Cleary's announcement. Davis called it a "great day for the PC Party, and for Newfoundlanders and Labradorians."

As expected, NDP Leader Earle McCurdy took the opposite view.

​"I think it's our party that got badly let down," McCurdy said, adding that the party will not be deterred by Cleary's decision.

"I'd rather it didn't happen. But the fact is, we have a great team of candidates and we have the platform and the values to go out and campaign hard with or without him."

Meanwhile, PC nominations for Windsor Lake opened Friday at 3 p.m., the same time that Cleary began his news conference, and will close Monday.