SOFIA, Dec 20 (Reuters) - The Bulgarian parliament approved the government's 2008 budget law on Thursday, with a fiscal surplus of 3.0 percent of gross domestic product, aimed at countering risks arising from growing external imbalances.

The 2008 budget set revenue at 27.2 billion levs ($19.94 billion), some 27 percent more than the initial plans for 2007. Spending, including a contribution to the European Union budget is set at 25.4 billion levs, up 21 percent on 2007 plans.

The new European Union member expects to end this year with a budget windfall of 3.5 percent, well above initial plans of 0.8 percent, in an attempt to dampen strong domestic demand that is likely to boost the current account gat over 21 pecrent of GDP.

Under the budget law, the government expects the external deficit to expand further to 21.9 percent of GDP next year. It sees end-2008, EU-harmonised inflation easing to 4.5 percent from an expected 9.3 percent this year.

Fiscal policy is the main tool for Bulgaria to influence the economy as the country has pegged its lev to the euro in a currency straightjacket that significantly curtails monetary operations.

Despite the planned budget surplus, the government plans to increase its capital spending by more than 50 percent to 4.25 billion levs next year, mainly for improving infrastructure.

Sofia will also increase social and education expenditure and aims to hike public wages and pensions by between 5 and 10 percent as of July.