The Swedish government and central bank's websites were closed down after a hacker attack Wednesday night.

"We've been hit by a DDOS attack," Riksbank spokesperson Fredrik Andersson told the TT news agency around 10.30pm on Wednesday.

The attack was made by the group Anonymous after a raid at hosting company PRQ, previous hosts to The Pirate Bay and WikiLeaks.

“It’s come to our attention that Swedish government raided PRQ servers in order to shut down numerous file sharing and torrent websites,” the Anonymous group wrote on a website 4chan on Wednesday.

“This has gone too far. This is unacceptable. Anonymous says this stops right now. You don’t fuck with The Internet… Today we hit their wallets hard.”

Payment systems between the Riksbank and the banks were not hit, the central bank said.

The attack came at the same time as the popular file-sharing site Pirate Bay suffered downtime. However, it was a mere coincidence, the Pirate Bay told the blog TorrentFreak. On Monday The Pirate Bay went offline, but is now back in business.

Attacked government bodies include the country's Health and Human Services Department, Security Service, Armed Forces and National Courts Administration, as well as Sweden's Bankers' Association.