Some 1,500 participants are expected to take part in the walk through Sisak on 1 May, observed in Croatia as International Workers' Day.
The protest march will highlight problems of the Sisak oil refinery, the Kutina-based Petrokemija artificial fertilisers producer and utility companies in Sisak.
A more detailed plan of the Labour Day events organised by the union federations will be presented at a news conference scheduled for 22 April.
Until this year, May Day parades were organised on 1 May in downtown Zagreb.