The central banks of Indonesia and South Korea have been hit by cyber attacks on their public websites since activist hacking group Anonymous pledged last month to target banks across the world, senior officials in the two countries told Reuters.

In response to the attempted hacks, Bank Indonesia has blocked 149 regions that don't usually access its website, including several small African countries, Deputy Governor Ronald Waas said in an interview late on Monday.

He said several central banks were hit by similar attacks and were sharing the IP addresses used by the perpetrators.