The Trudeau government is delaying implementation of firearm-marking regulations intended to help police trace guns used in crimes — despite a 2015 campaign pledge to immediately enact them.

The government announced Friday it will defer the regulations, which were slated to come into force June 1, until the beginning of December 2018.

It said the deferral will provide time needed to propose amendments to the regulations, first drafted in 2004, adding that details would be made available later this month.

The firearms community has long opposed the regulations and continues to "advocate against their coming into force," says an internal note to Public Safety Minister Ralph Goodale, recently obtained by The Canadian Press through the Access to Information law.

The regulations would require domestically manufactured firearms to bear the name of the manufacturer, serial number, and "Canada" or "CA," while imported guns would have to carry the "Canada" or "CA" designation along with the last two digits of the year of import.

The measures would help Canada meet the requirements of the United Nations Firearms Protocol and a convention of the Organization of American States.

"In addition to the treaty imperatives, firearms markings have value for domestic and international law enforcement as they, in conjunction with firearms records, can be used to trace crime guns," says the memo to Goodale from deputy minister Malcolm Brown.

Brown's ultimate recommendation to Goodale on the markings was stripped from the memo before release.

A history of delays

The previous Conservative government delayed the regulations several times.

In their election platform, the Liberals said they would "immediately" implement gun-marking regulations. The party also promised other, longer-term measures aimed at making it harder for criminals to get and use handguns and assault weapons.

In addition, the marking-regulation promise was included in a briefing book document prepared for the prime minister entitled "Key Commitments for Action in First 100 Days."

Some firearms advocates have argued the obligation to mark imported guns would mean acquiring marking technology or making arrangements for another company to apply markings, with an estimated cost of $200 per gun, according to a federal notice published in 2015.

However, an independent study commissioned by the government said the cost to stamp or engrave markings for Canadian manufacturers and large importers would range from nothing at all to $25 per firearm. It was not possible to gauge the impact on individuals and small importers.

Brown's memo to Goodale says many Canadian gun manufacturers exporting to the United States already mark their firearms in a manner that would meet or exceed requirements set out in the regulations to meet U.S. standards and at least one importer has voluntarily applied import marks.

Regardless, the memo says, the majority of firearms advocates and businesses are "strongly opposed" to the regulations due to the perception they would saddle manufacturers and importers with additional costs, while providing little public safety benefit.