SOFIA (Reuters) - Hundreds of Bulgarian policemen, firemen and prison guards staged a spontaneous protest on Tuesday against cuts to their pensions and benefits, testing the authority of the center-right government.

The demonstrators blocked major roads in the capital Sofia and held rallies in several other cities, demanding the resignation of Interior Minister Rumyana Bachvarova, who is trying to force through the changes.

Street protests have grown in Bulgaria, the European Union’s poorest member, in recent years. Voter frustration, especially with rampant corruption and organized crime, erupted in months of protests in 2013 and the country has had five governments in two years.

“This is a very risky wave of insubordination,” said Tihomir Bezlov, a political analyst at the Center for the Study of Democracy. “This is an uncalculated move with unpredictable consequences.”

Staff like police who are paid from the interior ministry budget are not allowed to strike, take a second job or join a political party; in return they are exempt from paying social security contributions.

But police are threatening to keep up daily protests and road blockades after negotiations with the finance ministry failed to result in the withdrawal of its 2016 budget plans. These include cutting lump sum retirement payouts to 10 times monthly net salary, from the current multiple of 20.

The measures would also slash annual paid leave to 20 days from 30, and reduce extra pay linked to length of service.

WIELDING THE KNIFE

“They have gone too far, and they hid this plan from us,” said a policeman protesting near parliament, who declined to give his name. “You can’t just cut with the butcher’s knife, without predicting the consequences.”

He said the changes, if passed, would cut his monthly wage by more than 30 percent. “They do not understand that Bulgaria may be left without police, and it is a tragedy.”

Police trade unions said that more than 250 staff under the umbrella of the interior ministry, including two directorate chiefs, had resigned in recent days, and hundreds more were considering doing so.

“We are discussing the best option in this situation,” said Bachvarova, who is also deputy prime minister. She will hold an extraordinary meeting with Prime Minister Boiko Borisov and Finance Minister Vladislav Goranov on Wednesday morning.

The interior ministry is the biggest employer in the Black Sea state, with nearly 50,000 people on its payroll.

Goranov said the government would save 25 million levs ($14 million) a year by cutting the social benefits, a sum which would allow the cabinet to improve maintenance and working conditions in the interior ministry.

Economists said reform of the ministry was necessary, but remained skeptical about whether the government would have the political courage to implement the unpopular move.

“I’m not optimistic,” said Georgi Angelov, an economist with the Sofia-based Open Society institute. “So far, none of the previous governments dared to make the reform.”

($1 = 1.7858 levs)