Conservationists are urging countries to slap trade sanctions on Mexico over its failure to rein in illegal fishing that could doom the vaquita marina porpoise to extinction within months.

With only around 10 vaquita believed to remain in their sole habitat off northwestern Mexico, environmentalists insist only "drastic measures" can rescue the world's smallest porpoise from disappearing altogether.

They are appealing to countries attending the Convention on International Trade in Endangered Species (CITES) in Geneva to wield the treaty's harshest sanction in a bid to force Mexico to ensure the vaquita's survival.

"The parties should sanction Mexico and put a ban on trade of CITES-listed species from Mexico until they get the situation under control," Zak Smith, Director of International Wildlife Conservation for the Natural Resources Defense Council (NRDC), told AFP.

CITES, which regulates trade in more than 35,000 species of plants and animals, has the power to sanction countries that break the rules or fail to rein in illegal trade in species protected under the treaty.