Mexican Interior Minister Santiago Creel and the outgoing US Homeland Security Secretary, Tom Ridge, have met for talks on improving border security.
President Bush has said a deal on Mexican immigration is a priority
They agreed to open crossings 24 hours a day at some of the busiest border checkpoints, and to try to cut queues.
But the two failed to make progress on an immigration deal giving Mexicans a right to work temporarily in the US.
The proposed guest workers' scheme is backed by President George W Bush but faces strong opposition, Mr Ridge said.
The plan, which would benefit millions of illegal Mexican immigrants in the US, has stalled because of security concerns raised by Republican politicians.
Mr Creel said he would continue to push for the right of Mexicans to work temporarily in the US.
He also criticised a ballot measure approved by voters in Arizona in November which requires people to show proof of legal immigration status to obtain certain government services.
"It's incompatible with human rights and does a disservice to both countries, the US as much as Mexico," he told reporters following the talks in the US border town of Calexico, 100 miles (160km) east of San Diego.
The Mexican government has given advice on crossing the border safely
Mr Ridge said reaching an immigration agreement was a "high priority" for Mr Bush in his second term.
But, he warned, pushing the temporary worker programme through Congress would be an uphill battle unless provisions were also brought in for stricter enforcement of immigration laws.
Mr Ridge stressed that the US would reject any proposal to offer an amnesty to Mexicans living illegally in the US.
He argued that other states would be unlikely to follow Arizona's measure if the US introduced a guest worker programme, because legal immigrants were less likely to need government aid.
Earlier this month, Mexico's government provoked criticism from US pressure groups by publishing a booklet giving safety tips to Mexicans thinking of crossing illegally into the US.
Mexico says it has a duty to protect its citizens, many of whom die each year crossing the long and dangerous border in the hope of finding work in the US.