The opposition conservative Civic Democrats, led by Mirek Topolanek, narrowly came out in first place, but face a difficult challenge in putting together a government as both right- and left-wing blocs each won 100 seats in the 200-member lower house of parliament.
The official results gave the Civic Democrats 81 parliamentary seats, the Social Democrats 74, Communists 26, Christian Democrats 13 and the Greens six.
That task appeared to become even harder after Prime Minister Jiri Paroubek, said he would propose taking his Social Democrat party into opposition after eight years in power.
"I will support our move into the opposition. I will announce that at the afternoon meeting of the parliamentary party's club" he said during a 90-minute discussion broadcast on national television.
Social Democrat leaders were due to meet again on Monday afternoon after no final decision on moving into opposition was taken.
A German-style coalition between the two main parties, is regarded as one way out of the post-election deadlock.
Mr Topolanek kept the door open for such an option.
"I do not exclude negotiations with the Social Democrats," he said during the television discussion.
Nevertheless Mr Topolank accused Mr Paroubek of "having an interest in a new election by questioning the last one."
Mr Topolanek will be given a first shot to solve the apparent election impasse.
Czech President Vaclav Klaus announced on Saturday night that he would ask the Civic Democrats on Monday to launch negotiations over forming a new government.
Mr Topolanek said he would create on Monday a committee of top party members to conduct negotiations.
"As the winner of the elections, we felt an even greater responsibility (to find a solution)," he said during the television debate.
The leaders, mostly looking calm despite the dramatic election result and a bruising election campaign, refused to "conduct negotiations on television."
Martin Bursik, leader of the Green Party which entered parliament for the first time, said it was not "pertinent" to discuss fresh elections the day after 65 percent of citizens had cast their votes.
’Stalemate’
Czech newspapers called the election result a stalemate, with Nedelni Svet saying the country finds itself on the verge of a constitutional crisis.
"It is a complete deadlock," political analyst Jiri Pehe told news agency AFP, adding that a German-style coalition might be the only solution.
"If that does not happen we will probably face early elections," he added.
"All possibilities apart from a grand coalition would be very fragile," added political analyst Tomas Lebeda.
Civic Democrats and Social Democrat leaders ruled out such a coalition during a bitter campaign that deepened the differences between them.
The two main parties are divided on many points with the Social Democrats favouring social justice, solidarity and progressive taxes while the Civic Democrats promise a flat 15-percent income tax, a smaller state bureaucracy and renewed privatisations.
Mr Paroubek on Sunday warned once again he was considering challenging the validity of the elections because of corruption allegations made four days ahead of the polls.
That prompted angry demonstrations in Prague, as supporters of the Civic Democrats expressed outrage at Prime Minister Paroubek's claim that the party used unfair tactics.