Bulgarians are voting in 2015's local elections on Sunday to pick mayors and municipal councilors.

They are also having their say on electronic voting, which some politicians say will not replace "tradiitonal" election methods but will boost activity and encourage turnout all around the globe, with more than 2 million Bulgarians living outside the country.

Nearly 12 000 polling stations opened at 06:00 local time (EET), 189 of them being mobile stations to help disabled voters or those living in remote areas. Another 294 stations are available abroad. Citizens are able to cast a ballot by 19:00 EET.

There are 6 372 548 eligible voters, official statistics have shown.

Seventy-one parties, three coalitions and three initiative committees are running, having produced a total of 42 000 candidates.

As many as 13 115 police officers are in charge of security on the day of elections.

A Central Electoral Commission told public broadcaster BNT, an hour into the vote, there had been no immediate reports of violations.

Electronic devices allowing voters to pick municipal councilors are available in several Sofia municipalities (Sredets, Triaditsa, Vazrazhdane) - and for the first time, voting by using them will count.

Holding the referendum itself has been a cause of Bulgarian President Rosen Plevneliev, who put it forward early last week as part of a question "package" on voting rules that included two more issues such as whether to make voting compulsory and the introduction of a full or partial majority system. These two, however, were turned down by Parliament.

For the first time in Bulgaria's history, people living outside the country will also be able to vote in the national poll.

A turnout of over 3.5 million people will make it compulsory for Parliament to put the question to a vote.

"Yes" answers taking 51% or a bigger share of the vote will make resutls binding for Parliament.