Podkrepa, one of Bulgaria's two big trade unions, is the only member of the National Tripartite Cooperation Council that opposes the government's plan for how the minimum wage will be set.

The government will decide next year's minimum wage, with no talks between employers and unions, but the new system will already apply. The amount will fall between €620 and €672.

Under the draft, the minimum wage will have a floor and a ceiling, and the ceiling is worked out with a formula that uses four indicators. The process has two stages. Unions and employers negotiate until 15 May, and by 15 August the Council of Ministers sets the amount for the next year.

The proposed system will leave minimum-wage workers worse off, and the union does not accept that, Podkrepa's chief economist Atanas Katsarchev told Bulgarian National Radio (BNR). "Under the formula on offer, the minimum wage loses at least €20 a month, which makes €480 a year."

The four national employers' organisations backed the rules. The agreement with the unions and the government dates from August this year.

Maria Mincheva of the Bulgarian Industrial Association told BNR: "Our goal is definitely not to shortchange anyone." She said the system should in future let the social partners take part, and that the wage should reflect both workers' needs and what the economy can afford.