Marijuana smokers in Colorado will be able to legally light up from January 1, but they'll have to pay the state government for the pleasure following a statewide vote.

Voters in the Rocky Mountain state approved a ballot measure to tax legally sold recreational marijuana, with a 15 per cent excise levy on wholesale deals and a sales tax of up to 15 per cent on retail sales.

The two taxes are projected to bring in $US70 million ($AU73.92 million) per year. Up to $US40 million ($AU42.24 million) of that money is earmarked for school construction, with the remainder slated to pay for state regulation of marijuana and drug education.

Colorado voted to legalize marijuana in last year’s federal election, with 55 per cent of voters in favour of the measure. The measure to tax the drug passed far more handily, with voters opting for the tax by approximately a two-to-one count.

A Democratic bill calling for an income tax increase to collect another $1 billion for an overhaul of the state’s funding system for its schools was shot down even as the marijuana tax was approved.

Supporters say the new taxes are needed to help fund overdue construction projects across the state and suggest that by taking the distribution of marijuana away from the drug dealers, crime rates will decrease and the overall quality of the marijuana sold will be increased through tight state-controlled regulation.

Opponents of the tax, however, said that by taxing the product, it would leave the door open for illegal marijuana sales, as the black market would be able to sell the drug without consumers being taxed.

Those new taxes on marijuana come on top of existing state and local taxes, meaning that consumers could pay as much as 38 per cent tax to purchase the drug in some areas.

Colorado and the state of Washington last year became the first states to legalise the recreational use of marijuana for people over 21, with the laws set to go into effect at the start of 2014.