LOS ANGELES (REUTERS) - Los Angeles, which has more storefront medical marijuana shops than any other United States (US) city, will close hundreds of the dispensaries and hike taxes on those that will be allowed to remain under a ballot measure approved by a wide margin of voters.

Nearly 63 per cent of voters supported Proposition D, which will cap the number of medical pot dispensaries at 135, compared with 37 per cent opposed, according to preliminary results released on Wednesday, the day after the vote.

Two rival measures that also would have placed new restrictions on the city's medical marijuana industry were defeated by wide margins.

At least 850 storefront medical cannabis shops are estimated to be operating in Los Angeles, the country's second-largest city, and some residents have complained that the dispensaries are a blight on their neighborhoods.