Prime Minister Justin Trudeau has shown he's prepared to accept some backbench grumbling about his small business tax reform plans — but only to a point. 

A Liberal MP who voted against the government on a Conservative motion related to the small business tax changes has been told he could face "consequences" for breaking party ranks.

Saint John–Rothesay MP Wayne Long supported a failed Tory move Tuesday that would have extended the consultation period on the government's proposed changes to the small business tax regime.

Long spoke to Liberal whip Pablo Rodriquez this morning, who indicated they were considering repercussions for such a vote.

"It's difficult conversations, I don't know if there will be consequences, but I have been told there may be consequences and I'm certainly prepared and ready to accept any decision the party makes," Long said in an interview with CBC News Wednesday.

"It wasn't a surprise, it wasn't said in a threatening tone, not at all. But the reality of it is, we're in unchartered grounds here. I came from being part owner and president of the Saint John Sea Dogs, a major junior hockey club, and I understand that sometimes when somebody breaks out of a norm of a team the powers that be have to look at that and they have to do what's best for the team."

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A spokesperson for Liberal whip Pablo Rodriguez said they do not comment on "internal matters." (Fred Chartrand/Canadian Press)

Asked for comment, a spokesperson for Rodriquez said they "don't comment on internal related matters."

Long said he would be "disappointed" if he is kicked out of caucus as he still broadly supports the government's agenda.

But Long said he could not sit idly by as the government pushes ahead with changes that could have consequences for proprietors in his riding, a move that opens a chink in Liberal armour.

'My constituents asked loud and clear for an extension, there's no way I could stand up in the House of Commons and vote against extending the process. I just couldn't do it' - Wayne Long, Liberal MP

"I just can't support a process that was only 75 days long that pitted people against each other. Doctors against nurses, put farmers on the defensive, and made lawyers, small business and professionals feel vilified," the backbencher said.

"It's not who we are as a party [or] what I believe in. I'm sorry to my colleagues who I know I've put in a very awkward position. I deeply regret this as you are such great representatives."

In voting for the Conservative motion, Long defied a whipped vote on a Liberal platform commitment. In the 2015 election campaign, the party promised to crack down on high-income earners using Canadian-controlled private corporations to reduce personal income taxes.

The Liberal government has shown a tolerance for MPs voting against the government line on private member's bills, and on legislation that was not explicitly promised in the last campaign, but standing against a major government initiative could be less warmly received.

At least one of Long's colleagues, Quebec MP Marc Miller, said while the New Brunswicker is a personal friend, he thinks something should follow such an act of defiance.

"Mr. Long took a very aggressive position and I believe there should be consequences, but I wouldn't exclude Wayne from my party. He's an extreme asset to it ... but I'm a firm believer in party discipline," Miller said.

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Finance Minister Bill Morneau has said he is open to tweaks to his small business tax proposals. (Fred Chartrand/Canadian Press)

Finance Minister Bill Morneau announced the tax proposals in mid-July. The consultation period ended Oct. 2.

The Conservative motion would have extended consultation until Jan. 31, 2018 — because of the "drastic negative impact on small- and medium-sized businesses," the motion said — but it was defeated in the House of Commons.

'I need to look in the mirror'

Long said he did a "massive amount of consulting" with constituents, who were overwhelmingly opposed to the changes. He said his riding has the largest concentration of small businesses in the country, and many doctors who work at the regional hospital.

Long said Tuesday he was elected by constituents of his Saint John riding to represent their views in Ottawa, not simply represent Prime Minister Justin Trudeau's government in New Brunswick.

Liberal MP slams 'tainted' tax reform consultations1:34

"My constituents asked loud and clear for an extension, there's no way I could stand up in the House of Commons and vote against extending the process. I just couldn't do it. I need to be true to myself, I need to follow my heart, and, in the end, I need to look in the mirror."

Finance Minister Bill Morneau's proposals have faced an onslaught of criticism, from farmers, to doctors, to tax professionals, premiers and other backbench Liberal MPs. Morneau signaled Tuesday he is now prepared to make changes to the proposals based on the feedback the government collected during the consultation period.

But Morneau was not at the Liberal caucus meeting Wednesday to actually explain to his fellow MPs — many of whom have been jittery for weeks about the changes — what tweaks he would be prepared to make.

This is the not the first time Long has taken a stance against changes that would tweak rules around income sprinkling and curtail passive investments — a tax-planning measure some use to shelter money earmarked for retirement.

The MP has said he think it's perfectly legitimate to use the current tax tools. "I believe that small business owners have that right because of the risks they're taking, for the people they're employing," Long said in an interview with CBC News last month.

"You can split hairs and say, well they can invest in an RRSP and they can still have money over in their passive account, but my philosophy is they deserve to have that money there."

With files from the CBC's Julie Van Dusen, Aaron Wherry