BUDAPEST, Hungary -- Hungarian trade unions on Saturday protested a government plan to raise workers' allowable overtime from 250 to 400 hours a year and the relaxing of other labour rules meant to offset Hungary's growing labour shortage.

The government says labour flexibility is needed to satisfy investors' needs -- like those of the German car companies whose factories help drive Hungary's economic growth -- and to allow workers looking to earn more to work longer hours.

Union leaders said that what they call the "slave law" proposals reflect the intention of Prime Minister Viktor Orban's government to boost companies' profits at workers' expense.

Laszlo Kordas, head of the Hungarian Trade Union Confederation, told several thousand protesters that Hungarians were working "at Europe's lowest wages."

Beside the increase in allowable overtime hours, which is the equivalent of adding a full day to the working week, unions are also the objecting to the extension to three years from one year of the period employers get to settle the payment of accrued overtime.

Also controversial is a proposal allowing employers to agree overtime arrangements directly with individual workers -- thereby bypassing the unions and the collective bargaining agreements.

"This process is only about the suppression of employee interests and the prioritization of the interests of employers and the powers that be," said Jozsef Szilagyi, co-chair of the Democratic League of Independent Trade Unions. "Those exercising political and economic power should understand that we are not robots."

The draft law was submitted to parliament by lawmakers from Orban's governing Fidesz party, allowing the government to avoid preliminary talks with unions and other interested parties. These would have been mandatory if the amendments to the labour code had been submitted by the government.

Reasons for the labour shortage include an aging population, higher wages elsewhere in the European Union, workers' low mobility within Hungary and the government's fierce resistance to immigration.

Parliament is expected to vote on the amendments on Wednesday, when unions may hold another protest.