ZAGREB (Reuters) - Several thousand people protested in Croatia’s capital on Saturday over government plans to raise the retirement age to 67 and cut pensions for those who retire early.

This week the government asked parliament to pass legislation lifting the retirement age of 65 from 2033 onwards, defending the reform as a step in efforts to make the pension system sustainable.

The bill also includes a proposal to cut the pensions of people who stop working before reaching retirement age by about four percent per year.

“There is a lot of misery and bitterness in us. Isn’t such a retirement proposal irresponsible towards our workers and pensioners?,” Kresimir Sever, one of the leaders of the trade unions that organized the protest, told the crowd gathered in central Zagreb.

Some of the demonstrators shouted “Thieves”, and many held banners accusing the government of impoverishing pensioners and workers. “From school to unemployment, from work to graveyard” read one of the banners.

Workers representing metal industry employees, nurses and other professions took turns to address the rally, saying they cannot work until the age of 67.

“I work in the rain and the burning sun. My legs and back have to carry hundreds of overloaded waste bins every day. I’ve already had a surgery on one knee, the other one will have to be treated soon,” a worker from a waste collection and disposal company, who said his name was Elvis, told the gathering.

Trade union leaders say the new law would particularly hurt older employees, who are often under pressure to retire earlier for health reasons or because the employers want to get rid of older staff. They have also pointed out that Croatians have a shorter life expectancy than people in many other European Union countries.

The unions have vowed to launch a campaign for a nationwide referendum to be called over the pension reform proposal if the government rejects their demands to scrap the plan.

For a referendum to take place, supporters of the ballot must collect the signatures of 10 percent of the electorate, equivalent to roughly 375,000 people.

Economic analysts and researchers say Croatia cannot make its pension system sustainable in the long term without increasing the retirement age.