The proposal, by the government-run Swedish Energy Agency, was part of a national plan for wind power use in 2020. It said the measure might be necessary to reach the European Union's target of using renewable energy sources for at least 20 percent of the bloc's power needs by that year.
"An ambitious renewable target for Sweden... could mean a need to build up to 30 terawatt hours of wind power in Sweden," the report said. "This means that the number of windmills needs to increase from nearly 900 to between 3,000 and 6,000."
Sweden's previous target was set at 10 terawatt hours of wind power by 2015.
The EU has yet to decide how to share the responsibility of increasing renewable energy among the 27 member states, but Sweden could expect a big increase, said Sara Bjursell, a senior adviser at the Swedish agency.
"This is because we have such good prerequisites for it, especially when it comes to wind power," Bjursell said. "It's a large country with long coastlines, mountains and a lot of space."
The agency's general director, Thomas Korsfeldt, said wind power would play a "key role" in increasing Sweden's share of renewable energy.
"An extensive expansion of wind power in Sweden is definitely a contribution to reducing the fossil fuel need on a European level," Korsfeldt said, according to the Dagens Nyheter daily.