Bulgarian President Georgi Purvanov has vetoed the country's new Electoral Code, citing constitutional and legal objections, returning it to Parliament for reconsideration of a wide range provisions.

In a lengthy memorandum setting out his reasons for returning the code, which was approved by Parliament after heated debate lasting several days towards the end of 2010, Purvanov said that an electoral code should be based on reasonable political compromises, or else it would be doomed to instability.

However, the code itself made it clear that it had been drawn up in the interests of a particular party, ruling party GERB.

GERB is headed by Prime Minister Boiko Borissov, with whom Purvanov - formerly leader of the Bulgarian Socialist Party before becoming head of state in January 2002 - has been involved in increasingly acrimonious public clashes in recent months.

The Electoral Code was drafted to govern a number of elections, including the 2011 vote - to be held on the same day - to elect a new President (to succeed Purvanov, who has reached his constitutional two-term limit) and municipal councils throughout Bulgaria.

Purvanov said that the Electoral Code had "many legal flaws".

Some of its provisions negated the achievements of the past 20 years in Bulgaria, as well as being in contradiction with standards for democratic elections in Europe, according to Purvanov.

Purvanov objected the code's residence requirements for eligibility to vote and to rules barring certain categories of people with dual citizenship from eligibility to stand as candidates.

These provisions, when included in the code, were widely seen as a move to curtail the practice of "voting tourism" which has benefited Bulgaria's Movement for Rights and Freedoms party, which is made up and led in the main by Bulgarians of Turkish ethnicity.

Purvanov also objected to the abolition of direct election of district mayors. Providing for these posts to be appointed instead of elected, he said, was a serious setback in the decentralisation of power.

On similar grounds, he took exception to the reduction in the number of places eligible to directly elect mayors. The Electoral Code raised the threshold for the number of people living in a town or village to be eligible for it to elect a mayor.

Purvanov said that the reduction in the number of members of municipal councils would disproportionately advantage those parties which got the most votes.

He also objected to the rules for the composition of the new Central Electoral Commission which would be in charge of all elections at all levels of government, saying that the new body would be "totally politicised".

Purvanov objected to a rule allowing absentee ballots to be cast only by people officially involved with the election.

He said that the rules governing voting gave an unfair advantage to people living in Bulgaria at the expense of expatriate Bulgarians.

Constititutionally, the veto of legislation by a Bulgarian President is not absolute, and can be overridden by Parliament without substantial difficulty.