The opposition MPs staged a symbolic protest on Sunday by gathering all the assembly's microphones and handing them over to the speaker, Igor Radojicic, before they boycotted the day's session, media reported from Banja Luka.
They claimed that emergency procedures had been improperly used on Saturday to adopt the entity’s budget for 2014 urgently, in time to meet a Monday deadline imposed by the International Monetary Fund.
Lawmakers from the opposition Serb Democratic Party, the Party of Democratic Progress and the People's Democratic Movement took part in the boycott.
But the majority in the Republika Srpska assembly, led by the Alliance of Independent Social Democrats, adopted a budget for next year of around one billion euro.
The Bosniak-Croat Federation entity also adopted its budget last week, but lawmakers in the state-level government have yet to adopt theirs.
Not meeting the deadline could leave Bosnia's state-level government and the governments of its two entities without a much-needed standby loan of around 50 million euro from the IMF, which they plan to use to fill budget gaps.
Unions also protested on Saturday in front of the Republika Srpska assembly building, demanding five per cent higher wages for state employees, but the pay rise they want was not included in the 2014 budget.