An ethnic Russian has become the first person convicted for involvement in a "cyber-war" on Estonia last year amid unrest during the removal of a Soviet-era war memorial, prosecutors said.

"Dmitri Galushkevich is the first hacker to be sentenced for organising a massive cyber-attack against an Estonian web-page," Gerrit Maesalu, spokesperson for the regional prosecutor's office in north-east Estonia, told AFP.

Galushkevich, 20, was fined 17 500 kroons (about R11 400) for piloting the attack between April 25 and May 4 which blocked the website of the Reform Party of Prime Minister Andrus Ansip.

"The young man admitted his guilt," said Maesalu.

"In deciding the verdict, the court took into account the fact that he had no criminal record," he added.

Prosecutors said Galushkevich, a student, had claimed the attack was an act of protest.

Ansip became a hate figure for a large slice of the country's ethnic Russian community after Estonian authorities decided to shift the so-called Bronze Soldier from central Tallinn to a military cemetery.

For Moscow and many among Estonia's Russian minority - which makes up around a quarter of the population of 1,3 million - moving the monument was an affront to the memory of soldiers who fought the Nazis during World War 2.

For many Estonians however, the statute was also a symbol of almost five decades of Soviet occupation, which ended when Estonia broke free from the crumbling communist bloc in 1991.

The site had become a flashpoint between Estonian activists and Russians marking Soviet-era anniversaries.

Four ethnic Russian activists are currently on trial in Estonia, accused of masterminding April 26-28 street violence in Tallinn as the statue was moved.

Galushkevich was the first individual to be tried over the cyber-attacks.

Several investigations are still underway.