(Adds referendum vote, governor quotes, details)
By Marja Novak
LJUBLJANA May 24 (Reuters) - Slovenia's parliament voted on Friday to change the constitution to ensure governments run balanced budgets from 2015, part of economic reform efforts to ensure the euro zone state will not need a bailout.
It also tightened the rules on referendums, which will no longer be held on laws involving taxes, the budget or human rights. Referendums instigated by trade unions and political parties have been used to block proposed reforms in the past.
Slovenia is struggling to curb a budget deficit that has soared since the global crisis ravaged its export-driven economy and is forecast to double this year to 7.9 percent of output.
Prime Minister Alenka Bratusek's two-month old government is racing to persuade financial markets and the European Commission that it can enforce long-delayed reforms and avoid becoming the sixth euro zone country to seek aid.
Bank of Slovenia governor Marko Kranjec said on Friday a bailout could be avoided by consolidating public finances, enforcing structural reforms and drawing foreign investment.
"The ball is in the government's side of the court," he told Reuters on the sidelines of a financial conference in Croatia.
Slovenia is the only ex-communist state in Europe not to have sold its main banks, which are choking on most of the financial sector's 7 billion euros ($9 billion) of bad loans.
"The parliamentary vote (on budget limits) is positive news as it shows that political consensus on important matters has finally been reached," said Saso Stanovnik, chief economist at investment firm Alta Invest.
"But the government will have to act fast and immediately start a complete reform of the public sector to bring down government spending as required by the amendment."
The yield on Slovenia's benchmark 10-year bond fell slightly to 5.9 percent on Friday, according to Reuters data, and analysts said it could decline further.
"The adoption of the fiscal rule and hopes of a more ambitious programme of fiscal consolidation as a result should be well received by the market, and by the European Commission," said Standard Bank analyst Timothy Ash.
The government has said it will sell Slovenia's second largest bank Nova KBM , main telecoms provider Telekom Slovenia, the Ljubljana airport, airline Adria Airways and 11 other companies to raise funds.
It also plans to raise value-added tax by 2 percentage points to 22 percent from July and reduce public sector wages.
Kranjec said the VAT increase would "certainly impact consumption and, later on, production", although that could be offset by a possible rise in exports. The central bank is sticking to its April forecast of a 1.9 fall in GDP this year.
Slovenia bought itself some time earlier in May when it sold two international bonds, raising $3.5 billion. It will need to return to the market early next year to refinance a 1.5 billion euro five-year bond which matures on April 2, 2014. ($1 = 0.7751 euros) (Reporting By Marja Novak, additional reporting by Igor Ilic in Croatia; Editing by Zoran Radosavljevic and Catherine Evans)