President George W Bush has reiterated his support for a "guest worker" programme which could allow millions of illegal immigrants to remain in the US.
Immigration and trade were high on the agenda at the summit
Mr Bush was speaking at the end of a two-day summit in Cancun with Mexican President Vicente Fox and Canada's Prime Minister, Stephen Harper.
He also spoke of new technology and closer cooperation to help increase border security between the neighbours.
The US Congress is currently debating an immigration bill.
More than half of the illegal immigrants in the US are from Mexico.
Hardline conservatives are strongly opposed to legalising undocumented immigrants and want to criminalise them.
Mr Bush made it clear that he was not in favour of allowing illegals to be put on a fast track to US citizenship.
But he called for a dignified debate on the issue, "in recognition that America is a land of immigrants and people ought to be treated with respect".
He also said a guest-worker programme would allow workers to do the jobs Americans did not want to do.
"I believe a guest worker programme will help us rid the society and the border of these coyotes who smuggle people in the back of 18-wheelers," he said.
"I believe it'll help get rid of the document forgers... I believe that it's important to bring people out of the shadows of American society so they don't have to fear the life they live."
However, he refused to say whether he would veto a bill by hardline conservatives that would criminalise illegal immigrants.
The House of Representatives has approved a bill making it a crime for them to remain in the US.
The bill touched off mass protests in US cities and now the Senate is working on a possible compromise that would reinforce border security while allowing work visas and eventual residency for some immigrants.
President Bush says his plans could improve border security
President Bush made it clear that any legalisation had to be matched by tighter security on the border with Mexico.
President Fox said Mexico and Central America had a role to play in tackling illegal immigration.
Mr Harper said Canada would also improve border security.
"Over the course of the next few months, we will be doing everything possible to ensure the security along our borders and to be able to move our merchandise back and forth," he said.
Trade issues were also a priority.
The three leaders vowed to forge economic ties in the face of competition from China and India.
In other developments:
- Mr Fox said he was preparing to extradite at least 24 drug traffickers to the US
- Mr Bush said he would resume negotiation with Canada on softwood lumber import tariffs
The US president is also expected try to address Canada's concerns over an American plan to require Canadians to show passports and not merely driver's licences when they cross the border.
All three leaders wish to repair relationships strained by the US invasion of Iraq - a decision both Mexico and Canada opposed.