The Senate has failed to reach a quorum to vote on the contentious blanket amnesty bill that could pave the way for the return from exile of former Prime Minister Thaksin Shinawatra.
The session required the attendance of 74 of the 149-member Senate, but 13 senators are away on overseas trips, while up to 30 are thought to be in the provinces. Members of the self-named Group of 40 Senators - most of who are appointed senators - also refused to attend the meeting.
The session began at 2.00pm but only 67 senators had registered their attendance.
Senate Speaker Nikom Wairatpanich called a 30 minute break of the meeting at 2.30pm. A number of senators arrived at parliament during the afternoon, but refused to attend the meeting.
Almost four hours after the session started, Mr Nikom announced that the meeting would be closed without a vote on the amnesty bill. The vote will take place on Monday instead, which is when it was originally scheduled for.
The government-backed bill would grant amnesty to leaders and others involved in political unrest since 2004.
The Senate vote on the bill was moved forward from Monday to today in what Thaksin's critics say was an effort to calm the protests, which have put heavy pressure on the government. Anti-Thaksin senators boycotted Friday's session.
Thousands of people have joined street protests this past week against the legislation, which they say is intended to let Thaksin escape a two-year jail term on a corruption conviction.
The lower house has already approved the bill.