State media in Iran says the government has approved plans to build 10 new uranium enrichment plants.
The government told the Iranian nuclear agency to begin work on five sites, with five more to be located over the next two months.
It comes days after the United Nations nuclear watchdog rebuked Iran for covering up a uranium enrichment plant, the BBC reports.
Western powers say Iran is trying to develop nuclear arms, but Iran says its nuclear programme is peaceful.
This latest announcement is a big act of defiance, which is likely to bring forward direct confrontation over Iran's nuclear programme.
President Mahmoud Ahmadinejad told his cabinet that parliament had ordered that Iran should produce 20,000 megawatts of nuclear energy by 2020.