The final count of votes in Bulgaria's three-point referendum may make its result binding in a surprise move, data from the election authorities shows.

If confirmed, the calculation will not match exit poll projections it does not meet the threshold.

With 85.64% of voter protocols counted, data released by the Central Election Commission (CEC) includes information based on 2 988 437 voters.

With 100% of ballots processed, the turnout will over 3 514 000, or above the line that makes results valid.

As many as 3 500 585 people - the number who voted in the parliamentary elections in 2014 - have to vote to obligate Parliament to accept the result.

The referendum asked Bulgarian voters whether the majority system should be introduced for elections, whether it should be made compulsory to vote, and whether state subsidies should be slashed to BGN 1, down from BGN 11 allocated per vote to parties that gained more than 1% support in general elections.

Those who took part in the poll overwhelmingly said "Yes" to all three questions.

Bulgaria already has compulsory voting, which was introduced earlier this year and used for the first time in Sunday's presidential election.

However, the referendum question also applies to national polls. Under the legislation currently in force, it is not mandatory to vote in referenda.