The Teamsters Union and the Sierra Club, staunchly oppose a pilot program that allows Mexican truckers to make deliveries north of the border, The Dallas Morning News reported Wednesday.

A lawsuit filed in federal court in San Francisco in August claims Mexican trucks do not meet U.S. safety standards.

Funding for the pilot program has also met with political opposition. Congress cut the funds for the program in December.

The U.S. Transportation Department restored the funds, but Sen. Byron Dorgan, D-N.D., the chair of the Subcommittee on Interstate Commerce, now says he will cut the funding again.

"This issue does affect the flow of goods throughout the region," North American Free Trade Association analyst Jeffrey Schott said. "But in terms of politics, energy, climate change and border security are much more important," he said.

A decision on the lawsuit is expected soon, the Morning News reported.