Finland is being targeted by a cyber activism campaign, police acknowledged Tuesday, after an apparent local branch of online "hacktivist" group Anonymous said it had hacked some 500,000 email accounts.

"It's beginning to look like a campaign," Timo Piiroinen of Finland's National Bureau of Investigation told AFP.

A group calling itself Anonymous Finland has claimed responsibility for a number of recent hacking incidents in the Nordic country, including hacking and publishing some 500,000 email accounts as well as nearly 15,000 passwords.

The personal identification and contact details of some 16,000 Finns were also leaked online in a separate incident earlier claimed by Anonymous.

Police said Finland had experienced random cyber attacks in the past, but that the current situation appeared different.

"There are common elements in the cases that suggest they are linked and we are investigating this," Piiroinen said.

Among the hacked emails are allegedly accounts belonging to journalists at Finland's mainstream daily Helsingin Sanomat, members of the Finnish parliament, police officials, Helsinki city councillors and students and faculties at several of the country's universities.

The hackers said they had taken advantage of security loopholes in company computer systems storing email addresses and passwords.

Anonymous Finland has also launched a campaign against the rightwing extremist Finnish Resistance Movement, leaking a list of its membership applications on October 31.

And on Monday, the group announced it was launching a series of cyber attacks against Finnish mining company Talvivaara, alleging its mining activities in Sotkamo in eastern Finland are conducted to "the detriment of the local natural environment and people of the communities".

Claiming the mining company routinely exceeds the maximum emissions permitted, Anonymous Finland said its attacks were linked to a global offensive dubbed "Operation Green Rights," described as "a series of actions in defence and safeguard of the environment."

The Finnish group appears to be a branch of Anonymous, a loosely-associated international group that has been involved in scores of hacking exploits, including the recent defacing of a website of Syria's defence ministry to protest at a bloody crackdown on anti-government protesters.