Prime Minister Yusuf Raza Gilani of Pakistan is holding emergency talks with members of the opposition, as his government battles for survival.
The coalition lost its parliamentary majority after the Muttahida Quami Movement (MQM) announced on Sunday it would go into opposition. It withdrew two ministers from the federal cabinet last week,
The MQM accuses the government of poor performance, especially on corruption and the economy.
The BBC reports elections may have to be held if the government cannot find new partners.
President Asif Ali Zardari on Monday expressed his full confidence in his prime minister.
Mr Zardari said in a statement he "solidly stands behind him in foiling any attempt to destabilise the coalition government".
The MQM was the second largest party in the coalition. A smaller coalition partner, the Jamiat-i-Ulema Islam party, pulled out last month after one of its ministers was sacked.
The coalition had 181 seats - including the MQM's 25 - in the 342-member parliament.
Other meetings
The MQM's departure leaves Mr Gilani's Pakistan People's Party well below the 172 seats needed to preserve its majority.
On Monday, the premier is due to meet Shahbaz Sharif, president of the Pakistan Muslim League - the biggest opposition party in the National Assembly.
The PML-N - which rules Punjab province - was previously a partner in the ruling alliance, but withdrew two years ago because of political differences.
Mr Gilani is also due to meet the leader of another major opposition party, the PML-Q, on Monday.
The National Assembly is due to hold its first session of the new year later in the day.
