Municipal politicians have approved a resolution that rejects the expansion of oil tanker traffic through British Columbia coastal waters, but only by the narrowest of margins.

Delegates attending the annual Union of B.C. Municipalities convention voted 51 per cent in favour of a resolution to oppose projects leading to expanded oil tanker traffic.

The resolution also calls on Premier Christy Clark and Opposition New Democrat Leader Adrian Dix to use legislative powers to prevent oil tanker expansion.

The vote prompted a response from Enbridge Inc., saying its proposed Northern Gateway pipeline project from Alberta to B.C.'s northwest coast incorporates world-class marine safety measures to protect the coast and its people.

Enbridge says for more than 25 years, more than 1,500 vessels carrying petrochemicals have navigated in and out of the northwest port of Kitimat and about 250 tankers travel to Vancouver every year.

The UBCM resolution says a crude oil spill would have devastating and long-lasting effects on B.C.'s coast.