NEW ORLEANS - Prime Minister Stephen Harper praised outgoing U.S. President George W. Bush for never promising anything he could not deliver as the two began a 48-hour North American leaders' summit.

But it was unclear Monday whether anything will be promised, much less delivered, during the fourth annual Security and Prosperity Partnership meeting among Harper, Bush and Mexican President Felipe Calderon.

With Bush in the final months of his presidency and the U.S. political stage dominated by the bitter Democratic party primaries, this year's version of the "Three Amigos" summit looks like a curtain call.

"What I appreciate most, what I've appreciated in our relationship over the past couple of years, is the fact that whether we agree or disagree, we're always able to talk very frankly, very upfront," Harper said at a photo opportunity Monday after an hour-long meeting with Bush.

"The president has never promised me anything he couldn't deliver and that's always appreciated."

Harper noted he and Bush will meet at least once more at a summit - this year's G8 in Japan.

For his part, Bush thanked Harper for his "strong and effective leadership" at a NATO summit earlier this month in Bucharest.

He also gave an endorsement of the North American Free Trade Agreement, which has come under fire from Democratic hopefuls Barack Obama and Hillary Clinton.

"I'm a strong advocate of free trade," said Bush. "And I believe it's in our nations' interests that we continue to have a free trade arrangement."

Bush said the summit "comes at an opportune time" to illustrate the benefits of NAFTA.

Yet despite its lofty name, the two-day meeting is more about technical co-operation and cutting red tape than dramatic dealmaking.

A widely diverse grab-bag of issues is up for discussion, ranging from carbon sequestration to border crossings and hemispheric politics.

Harper, who sat down with Calderon later Monday before the three leaders met for a working dinner, suggested he and Bush had discussed the Afghanistan mission during their talk.

The U.S. and Mexican presidents, meanwhile, reopened the Mexican consulate and heralded it as a sign of close ties between the neighbouring countries and a reason to celebrate the rebirth of New Orleans following hurricane Katrina.

"I chose New Orleans for our meetings with Mexico and Canada because I wanted to send a clear signal to the people of my country that New Orleans is open for business," Bush said. "It's a good place to visit and the after the devastation of Katrina, it's become a hopeful city."

If there's a theme to this year's Security and Prosperity Partnership meeting, it appears to be about promoting the venue and not the partnership itself.

But not everyone was happy that the leaders were sticking to the historic city's stately high ground and foregoing a tour of the still-ravaged poor neighbourhoods in the Lower Ninth Ward.

"There's a lot of frustration there two and half years later," New Democrat MP Peter Julian said after speaking with community activists and surveying the pile of rubbish still left in empty neighbourhoods.

While the leaders were eating at a five-star restaurant in the Garden District among old plantation homes that have never seen hurricane flooding in 200 years, lower in the city people are still digging out.

"It's a bizarre juxtaposition," said Julian, "just like the SPP itself."

As is usual at such gatherings, security was heavy - although no protesters were evident in the sultry bayou heat.

Sand-coloured military vehicles lined the street outside the hotel where the leaders convened, and the media path to the Bush-Harper photo-op was a steeplechase of sniffer dogs, metal detectors, holding rooms, a single secure elevator and two flights of back stairs.

If a prevailing issue is on the agenda, it is trade.

The three countries already share the largest trading partnership in the world, totalling nearly US$1 trillion a year. Heading into the meeting, Bush said he plans to talk to Harper and Calderon about expanding trade in the Western Hemisphere.

The timing comes as the United States is mired in an economic slide, and many displaced workers and labour leaders blame trade for shipping jobs overseas. The 14-year-old NAFTA has become a lightning rod.

Clinton and Obama both have threatened to pull the U.S. out of NAFTA as a means to pressure Canada and Mexico to negotiate more protections for workers and the environment.

- With files from The Associated Press.