A trade pact between Australia and 10 other nations has collapsed at the last minute after Canada baulked without warning.
Prime Minister Malcolm Turnbull hoped to seal the revived Trans-Pacific Partnership deal at the Asia Pacific Economic Cooperation summit in Vietnam.
The 11 nations involved had worked in overdrive to resurrect the trade deal this week, which first fell apart after Donald Trump withdrew the United States.
But Canadian Prime Minister Justin Trudeau blew these plans apart after reneging on an agreement all trade ministers including his own had struck just hours earlier.
Australia, Japan and other countries pushing hard to get the deal over the line were furious with Mr Trudeau's no-show on Friday evening.
It was not immediately clear what sparked Canada's about-face, but the country had been insisting this week it would not be rushed into signing onto a deal.
Australian Trade Minister Steven Ciobo, who was in Vietnam for the negotiations, was deeply disappointed but remained diplomatic.
"There is of course still opportunity for us to continue discussions to try to work our way through the last remaining issues Canada raised," Mr Ciobo told reporters in Da Nang.
"But at this point in time it would appear, at the request of Canada, we've been unable to have leaders achieve a resolution today."
Mr Ciobo would not be drawn on whether Canada could be cut adrift, leaving the nine other countries to push on with the trade pact without them.
Earlier, Mr Trump effectively slammed the door shut on any hope of America rejoining the TPP negotiations during his address to the APEC summit.
The US president said he was willing to strike trade deals with Pacific nations, but only on a country-to-country basis.
"I will make bilateral trade agreements with any Indo Pacific nation that wants to be our partner and that will abide by the principles of fair and reciprocal trade," Mr Trump said on Friday.
"What we will no longer do is enter into large agreements that tie our hands, surrender our sovereignty, and make meaningful enforcement practically impossible."
Australia will still walk away from the APEC summit with a free trade pact with Peru that will eliminate nearly all tariffs exporters face into the Latin American country.
The Peru agreement is a significant boost for Australia's sugar industry, farmers and mining services firms.
Mr Turnbull is due to mark Remembrance Day alongside his New Zealand counterpart on Sunday before holding several meetings and departing for Hong Kong.