A group of leftist Mexico City lawmakers have introduced a bill to legalize the sale of marijuana in the nation's capital.

The initiative proposed by members of the Democratic Revolution Party seeks to supply marijuana to users and regulate the amount they can buy. It would create a health program to monitor consumption and sale.

Lawmaker Vidal Llerenas, who proposed the bill, says the objective is to allow authorities to focus on more serious crimes.

Since 2009, Mexico has allowed the possession of 5 grams of marijuana, about four joints, for personal use.

The local proposal is accompanied by an initiative at the federal level, which proposes increasing that amount to 30 grams. The federal proposal also wants to regulate the cultivation and processing of the plant.