Uruguay, the first country to fully legalise the production, sale and distribution of marijuana, has called for bids from private growers who want to farm cannabis in a public field.

Open until August 18, the tender from the newly launched Institute for the Regulation and Control of Cannabis (IRCCA) seeks up to five growers who will get a licence to farm marijuana plants at a government-run field and sell it to consumers.

The growers will be allowed to produce and distribute a total of one to two tons of cannabis per year, to be sold at pharmacies for about $US1 ($A1.08) a gram.

The plots up for bidding are all on a single field in the southwest of the country whose perimeter will be guarded 24 hours a day, officials said.

Uruguay passed a law allowing the legal cultivation and sale of cannabis in December last year, creating a state-regulated market that controls the production chain from seed imports to final sales.

Under the law, users who sign up for a national registry - which has yet to be set up - will be able to grow marijuana themselves, buy it at a pharmacy or join a distribution club, consuming a maximum of 40 grams a month.

Regulated sales are expected to start early next year.

The government estimates that 150,000 of the country's 3.3 million people will sign up for the program, with annual production of around 20 tons of cannabis.