Uruguay has become the first among all nations of the world to legalise the production and sale of the marijuana cannabis drug.

On Tuesday, the small South American nation's Senate voted 16-13 to finally formalize legalise the growing, sale and smoking of marijuana in the country.

"Uruguay has taken a step forward," Sen Luis Rosadilla from the ruling Broad Front party said. "We'll see how it works, and we'll continue looking for solutions."

Once President Jose Mujica signs the law, marijuana cannabis users in Uruguay over the age of 18 can now purchase a maximum of 40 grams (1.4 ounces) per month from licensed pharmacies. Users however need to be registered first in a government database - a requirement to monitor their monthly purchases.

One hundred twenty days after the law is implemented, Uruguay residents may grow six marijuana plants in their homes per year, or as much as 480 grams (about 17 ounces). Smoking clubs with 15 to 45 members can grow up to 99 plants per year.

Uruguay's legalized weed however won't be made available to foreign tourists as these wont be allowed to cross the borders.

"There are a lot of doubts and the doubts are legitimate," Mr Mujica, a former leftist guerrilla fighter, said in a televised interview with Channel 4. "But doubts shouldn't paralyze us in trying new paths to deal with this problem that has gripped us."

"We are not totally prepared. But as in everything, you have to give it a chance," he added.

Buying and selling of the marijuana cannabis drug will start selling in Uruguay over the counter from licensed pharmacies in April, but only to registered drug users.

"We begin a new experience in April. It involves a big cultural change that focuses on public health and the fight against drug trafficking," Uruguay's first lady, Senator LucÃa Topolansky, told Reuters.

As the first among the world's nations, this precedent will be greatly scrutinized and monitored by the more developed countries.

"This development in Uruguay is of historic significance," Ethan Nadelmann, founder of the Drug Policy Alliance, told Reuters.

"Uruguay is presenting an innovative model for cannabis that will better protect public health and public safety than does the prohibitionist approach," Mr Nadelmann said.