Hundreds of protesters rallied on Monday for a third day in Kyrgyzstan's capital Bishkek to call for the resignation of PM Felix Kulov.
They said he was indirectly responsible for the death of an MP who was shot by inmates as he visited a jail last week.
The demonstrators, who have set up traditional felt tents in front of parliament, are led by the victim's brother, Ruspek Akmatbayev.
Popular protests drove President Askar Akayev from power in March.
Parliament was due to discuss the murder in an emergency session on Monday, but failed to reach a quorum.
"If the parliament does not vote to dismiss Kulov [on Tuesday], we will demand that it be dissolved," AFP news agency quoted Mr Akmatbayev as saying.
20 October: MP Tynchbek Akmatbayev and two aides shot dead during prison visit
22 September: MP and businessman Bayaman Erkinbayev shot dead
13 June: Security guards open fire on protesters in Osh, injuring at least seven
10 June: MP Jyrgalbek Surabaldiyev shot dead in Bishkek
1 June: Hundreds eject protesters from Supreme Court which they had held for more than a month
He has accused the prime minister of having ties to a criminal detained in the prison. The prime minister denies this.
Mr Akmatbayev himself is accused of involvement in the murder of a top anti-corruption official. He is awaiting trial.
The BBC's Ian MacWilliam says the protest is a sign of unresolved political tensions in a country that has become very difficult to govern since President Akayev was ousted.
The circumstances surrounding the prison shooting are still not clear.
According to a government report, the MP was armed when he entered Moldavanovka prison about 25km (15 miles) outside the capital.
Mr Akmatbayev and his entourage had gone to inspect living conditions at the prison following a wave of protests by inmates.
Some reports say he had been rude to some of them, and this might have sparked a violent reaction.
Tynychbek Akmatbayev is the third MP to be killed since March.
Two other deputies were shot dead in killings that may have been related to business rivalries.
Kyrgyzstan has witnessed several violent incidents since the overthrow of President Akayev.