"I'm very much saying today if people want to have a street party, don't listen to people who say it's all bureaucracy and health and safety, and you can't do it," Cameron said.
"It's very important to understand if anyone wants to have a street party you don't need a food license, you don't need an entertainment license, you don't need to have written documents about closing your street. ... If you do want to celebrate with Catherine and with William, you should go ahead and do so."
The prime minister was responding to persistent reports that councils are putting up roadblocks to parties planned to mark the union of Prince William and Kate Middleton.
In addition, the anti-monarchist group Republic says its plans for a "not the royal wedding" party are being blocked by London's Camden Council.
Republic said the council approved the party last month, but has since said it will not close the street to traffic for the day.