A former Hungarian prime minister says he is on a week-long hunger strike to call attention to planned changes to the electoral law which he says limit voters' rights.

Ferenc Gyurcsany, who resigned in 2009 and now leads the small Democratic Coalition, said Monday that plans to introduce voter registration ahead of the 2014 parliamentary elections would limit democracy and help the government strengthen its grip on power.

Prime Minister Viktor Orban's Fidesz party says registration is needed in part to keep track of the many Hungarians living in neighboring countries who have obtained citizenship in the past few years.

Gyurcsany and three other party members will remain in tents outside Parliament for the strike's duration, where they will digest only fluids and vitamins.

The strike started late Sunday.