Serbia's parliament was set to convene its first session Tuesday, weeks after contested elections were hit by allegations of electoral fraud.
The Balkan nation's electoral commission said President Aleksandar Vucic's ruling Serbian Progressive Party (SNS) had secured a commanding victory by winning 46.75 percent in the parliamentary vote.
The main opposition camp -- known as the Serbia Against Violence (SPN) coalition -- received just 23.66 percent.
But international observers reported irregularities during the polls -- including "vote buying" and "ballot box stuffing" -- while some Western nations voiced concern over the electoral process.
And the opposition has zeroed in on controversy involving tight races in local contests in Belgrade, accusing the government of allowing unregistered voters from neighbouring Bosnia to cast ballots illegally in the capital.
Following the election in December, thousands joined protests that included an attempt to storm Belgrade's city hall.
The opposition pressed for the annulment of vote -- a request that was denied by Serbia's top court.
The opposition said it had no plans to formally boycott participating in the government but hinted that they would take unspecified "actions" during Tuesday's parliamentary session.
"We will act there," opposition leader Miroslav Aleksic told public broadcaster RTS.
"We want to be there so that we can have the opportunity to tell future representatives and above all, citizens, that election fraud took place and that domestic institutions are either silent or complicit," another opposition leader, Marinika Tepic, told N1 news channel.
Vucic has largely brushed aside the protests and legal manoeuvres by the opposition to overturn the polls' results.
The European Parliament was set to decide on a resolution regarding Serbian elections on Thursday, a debate which also drew rebuke from the ruling party.
"This has nothing to do with the elections ... This is related to the fact that they (MEPs) support those who push their agenda in the Republic of Serbia," Serbian prime minister Ana Brnabic told pro-government Pink TV.
