HALIFAX -- An apparent row over the Yarmouth to Maine ferry led the Nova Scotia Progressive Conservatives to walk out of the legislature in protest Wednesday.

The walkout came after Tory Leader Tim Houston alleged that he had been assaulted during a heated verbal argument over the ferry with Education Minister Zach Churchill on Tuesday.

Houston told the legislature that Churchill had followed him into a phone booth in the members' area and grabbed him by the shoulders during the confrontation. He said Churchill also later made "profane, aggressive, and threatening remarks" about Houston's pending participation in the upcoming meeting of the economic development committee.

"These incidents individually and in totality clearly constitute the execution of a threat and intimidation in an attempt to prevent me from performing my function as a legislator, as an elected representative for my constituents and as a member of this assembly," Houston told the house.

Houston moved that the allegation be investigated by the house internal affairs committee, but that was voted down by the majority Liberal government, prompting the walkout.

Outside the legislature, Houston explained his version of events to reporters.

"He entered the small phone booth, put his hands on my shoulders and had some very heated comments for me. I told him to get his hands off me and get out," Houston said.

Houston said he believed the walkout by his party was important, given that it gave up its opposition day during question period.

"It was very clear the majority government wanted this shut down very quickly and they achieved their goal," he said.

Churchill denied assaulting Houston but admitted to a heated argument he said the Tory leader initiated.

"The member said, 'I've got you on the ropes,"' he told the legislature. "'You might save your seat but that ferry is going to take down your government."'

Churchill later told reporters that he didn't grab Houston by the shoulders.

"I realized we should probably calm it down," he said. "I did reach out and I touched his arm to try to shake his hand and I said we should calm down. His response was, 'Get your hands off me, get a life."'

Only two other members were in the vicinity of the incident, Tory member Larry Harrison and Public Service Commission Minister Tony Ince.

Harrison said the argument escalated and he did hear Houston say "get your hands of me," however he said he didn't see the alleged assault.

Ince also said he didn't see the incident, but he decided to step in and remove Churchill from the situation after hearing shouting and Churchill say "take it easy."

Premier Stephen McNeil told reporters he believes Churchill's account of a heated argument and believes the incident doesn't require an investigation by internal affairs.

"There was no evidence presented today on the floor of the legislature other than two members raised their voice," McNeil said. "Is that appropriate? We can argue that, but that's not something that would go to that committee."

Houston rose in the house following a meeting of the economic development committee, where the ferry's private operator appealed to opposition politicians to tone down the rhetoric about the heavily subsidized service, saying it is disruptive to the business.

The appeal came after the government was criticized for committing $8.5 million to renovate the ferry's new U.S. port in Bar Harbor, Maine.

Bay Ferries CEO Mark MacDonald said he hoped politicians can "stay calm, rational, and measured" with what they say and do.

MacDonald said negative comments that are "excessive and nasty" hurt revenue, although he couldn't quantify how much. He said the service takes in about $2-million for every 10,000 passengers, and negativity complicates dealings with travel operators and consumers.

"It's destructive to the business not only in the broad sense, but it actually costs us dollars," he said. "If it costs the ferry service dollars it ends up costing the taxpayer dollars."

MacDonald said the current lawsuit by the Tories to gain access to his company's management fee illustrates his point.

"To my understanding it was announced at a political convention and there were photo ops and everything else," said MacDonald. "File the appeal, put it before the courts, see what the courts say and get on with it. But don't try and turn it into a stunt."

Meanwhile, Transportation Department officials said they believed they can get the ferry's annual provincial subsidy down to about $10-million or lower once the service is stabilized following the move of its Maine port from Portland to Bar Harbor.

Royden Trainor, senior executive director of policy and planning, later told reporters the subsidy could be reduced within two years.

Last week the province announced it would provide another $13.8 million for the ferry's operations in 2019-20. That figure is up from the $10.9 million spent in the 2018 sailing season.