LJUBLJANA (Reuters) - Most schools and kindergartens in Slovenia were closed on Wednesday for the second time this year as teachers staged another one-day strike for higher wages.

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Some 40,000 teachers went on strike and around 15,000 attended street protests in 11 Slovenian cities at noon, according to their trade union SVIZ.

In the largest protest, about 3,000 people gathered in front of the government building in the capital Ljubljana. Teachers blew whistles and waved union flags and banners.

“Teachers - big heart, small salary” one banner said. Another showed a sketch of Prime Minister Miro Cerar with a long nose to suggest the government failed to keep its promises on wages.

“The work of a teacher is undervalued. We have to do a lot of work but our wages do not match our responsibilities,” Ludvik Mihelic, who teaches geography at a school for economics in Ljubljana, told Reuters.

Teachers, who demand wage hikes of 8 to 12 percent, held their first strike a month ago and plan to hold the next on April 17 unless the government meets their demands.

The pre-tax monthly wage of teachers is about 500 euros lower than that of similar public sector employees, the head of SVIZ Branimir Strukelj, told reporters.

Other public sector unions including nurses, social workers and customs officers are also threatening strikes over wages.

The government gave no immediate comment. Finance Minister Mateja Vranicar Erman said on Tuesday the government needed to press ahead with its economic policies to secure the country against the next financial crisis.

Slovenia narrowly avoided an international bailout for its banks in 2013 but returned to growth a year later. The government expects the economy to expand by at least 3.9 percent this year versus 5 percent in 2017, boosted by investments and exports which include cars, car parts and pharmaceuticals.

Three months ahead of general election, which is expected on June 10, the center-left government is under heavy public sector wage pressure as trade unions claim economic growth offers room for higher wages.

However, no party has received a direct electoral boost from the strikes.

The government had said total union demands amount to almost 1 billion euros, adding most cannot be met because they are not justified by productivity and GDP growth and would threaten the planned fiscal consolidation.

Slovenia plans to run a budget surplus of 0.4 percent of GDP this year versus a deficit of 0.8 percent in 2017.