Oakland, California - Voters in the California city of Oakland have resoundingly approved a tax on medical marijuana, the first such tax of its kind in the US.

The 1.8 per cent levy will be imposed on all sales of medical marijuana at the city's licensed dispensaries, which sold some 20 million dollars worth of the substance last year. It was passed by some 80 per cent of voters in a mail-in ballot, election officials announced late Tuesday.

The vote comes as the city and the state of California face a massive budget crisis and politicians increasingly see a marijuana tax a way to raise revenue.

"It was the perfect moment," said councilwoman Rebecca Kaplan who proposed the measure. "We had a horrible budget crisis in the city, and we were looking for revenue."

State tax authorities last week released an estimate that California could raise 1.4 billion dollars with a cannabis levy. The Los Angeles City Council proposed a medical marijuana tax earlier this month, and the cities of Berkeley and San Francisco may consider similar legislation.(dpa)