Negotiators from the remaining members of the Trans-Pacific Partnership (TPP) gathered in Canada on Tuesday seeking ways to boost free trade in the region after the United States pulled out of the 12-nation pact.

The withdrawal killed off years of negotiations and left the region looking for ways to deepen economic ties without a United States that appears increasingly suspicious of multilateral deals.

The two-day meeting of senior officials in Toronto will deliver recommendations in time for an Asian trade ministers' meeting in Vietnam later this month.

Japanese Finance Minister Taro Aso said last month Tokyo would not rule out the option of negotiating a TPP-type agreement without the United States.

Joseph Pickerill, chief spokesman for Canadian Trade Minister Francois-Philippe Champagne, said officials will be looking at what kind of free trade arrangement or framework for the region would receive the most support.

"I wouldn't characterize it as being TPP part two," he said.

Asked about the chances of pressing ahead with "a TPP-minus-one deal," Champagne said on Monday: "We're going to see, and that's why we're meeting next in Vietnam. But what's important now is to look at all options".

President Donald Trump pulled the United States out of the TPP in late January, complaining about "ridiculous trade deals" he said had damaged the U.S. economy.

In March, Canadian Foreign Minister Chrystia Freeland said the TPP as originally drawn up could not exist without U.S. ratification, adding that some "sort of other combination of TPP interested countries could happen".