Pot smokers in Uruguay on Tuesday became the first in the world to sign up to buy state-vetted cannabis for recreational use, as pharmacies aim to start selling it in July.

Far from the cannabis cafes of the Netherlands and other states that have decriminalised pot, this small South American country is the first to fully legalise consumption of the drug all the way from production to sale.

Already allowed by the leftist government to grow the weed in their homes and smoke it in clubs, Uruguayans in a few weeks will be able to buy it from the chemist along with their shampoo and aspirins.

"This is a great step forward in the evolution as citizens," said Marcos Ferreira, 41, one of the people queuing in a small line to sign on to the Cannabis Register at a post office in central Montevideo.