OTTAWA -- Finance Minister Bill Morneau is threatening to sue the Conservatives for suggesting he used his inside knowledge of a pending tax change announcement in 2015 to sell off stocks before their value dropped.

On Tuesday, a day after sidestepping more than a dozen questions on the issue, Morneau called the insinuations by Tory finance critic Pierre Poilievre "absurd."

"If the Opposition want to continue with these absurd allegations, which have no basis in any sort of fact, they take them outside of the House and I will give them a sense of exactly how our legal system works," said Morneau.

Anything said in the House of Commons is subject to parliamentary privilege, which gives MPs legal protection from libel and defamation laws. Poilievre first raised the allegations Monday during question period in the Commons.

He claimed Morneau's December 2015 announcement that he would raise income taxes on the highest earners caused the entire stock market to drop, including the value of Morneau Shepell shares -- 680,000 of which were sold off roughly a week earlier.

Poilievre alleged the early sale of the shares saved the owner half a million dollars.

He repeatedly asked Morneau if it was a coincidence that the 680,000 shares were sold off a week before the tax announcement. And he asked Morneau repeatedly to confirm he was the "someone" responsible for selling off those shares in the company founded by the minister's father.

When the Speaker questioned the appropriateness of questioning the government on the matter, Poilievre retorted: "It is actually the responsibility of government to ensure that no minister ever uses inside knowledge to benefit from transactions on the stock market."

While Morneau dodged those allegations of insider trading Monday, he had more to say at a hastily called news conference Tuesday.

"What we're hearing now is in my mind (an) absolutely crazy idea that something that we campaigned on, that we talked to 36 million Canadians about which was a rise in taxes in the top one per cent was somehow knowledge that was only my knowledge," he said.

Poilievre maintained he hasn't "actually accused him of anything" and has only asked Morneau whether he was the one who sold the shares a week before the tax announcement.

"I am absolutely confident that everything I've said out there and in here is true," Poilievre said in the Commons, challenging Morneau to meet him outside the chamber to answer the question.

Morneau was not present during question period Tuesday because he said he had a speech to deliver in Toronto. But under continued Conservative attacks over the stock sale, Prime Minister Justin Trudeau asserted that the finance minister "continues to focus on the things that matter to Canadians and he has our full confidence."

On Dec. 7, 2015, the day of Morneau's tax-change announcement, the Toronto stock index fell 2.4 per cent for its single weakest day of the quarter, BMO chief economist Doug Porter said after he was asked to look up his notes.

Porter said already-low oil prices dropped "heavily" that day -- by five per cent. He said that factor alone may have been responsible for much of the weakness in the market.

Nevertheless, the New Democrats also applied pressure Tuesday on Morneau over the 2015 stock sale. The NDP has asked the ethics commissioner to look into Poilievre's allegations.

The ethics commissioner has already launched a formal examination to determine if Morneau was in a conflict of interest when he introduced pension-reform legislation, which critics have insisted would benefit Morneau Shepell -- a company in which, until recently, Morneau owned about $21 million worth of shares.

After the ethics controversy erupted, he sold off the remainder of his holdings in Morneau Shepell and vowed to place his other substantial assets in a blind trust.

Morneau donated to charity the difference between what the shares were worth at the time of the sale and their value in 2015 when he was first elected -- an amount estimated at about $5 million.

He has also faced intense criticism about his integrity after information surfaced showing that, based on the ethics commissioner's advice, he did not divest shares or place his holdings in a blind trust after being was named to cabinet.