The attacks are reported to be in response to the Tunisian government's attempts to block access related to leaked WikiLeaks cables that related to the African country.
According to Graham Cluley, senior security researcher with Sophos, Tunisia and other Arab nations have attempted to control the flow of WikiLeaks-related information into their country by blocking websites and banning overseas newspapers.
In his security blog, Cluley claims that members of the Anonymous group – who have staged a series of DDoS attacks on MasterCard, Visa and other sites last month – were conversing on Sunday via Internet Relay Chat (IRC) channels to work out which Tunisian sites to attack.
"Impacted websites that appear to have been brought down by the distributed denial of service (DDoS) attack include that of Tunisian president Zine El Abidine Ben Ali and the government's official website", says Cluley.
A statement posted on Anonymous-related websites, meanwhile, is reported to single out the Tunisian government for criticism, noting that it wants to control the present with falsehoods and misinformation in order to impose the future by keeping the truth hidden from its citizens.
"We will not remain silent while this happens. Anonymous has heard the claim for freedom of the Tunisian people. Anonymous is willing to help the Tunisian people in this fight against oppression. It will be done. It will be done", says the posting.
"This is a warning to the Tunisian government: attacks at the freedom of speech and information of its citizens will not be tolerated. Any organisation involved in censorship will be targeted and will not be released until the Tunisian government hears the claim for freedom to its people"," the Anonymous posting adds.
Cluley notes that anyone signing-up to join in the attacks on the websites of various governments should remember that participating in a DDoS attack is against the law.