Greece's fourth-largest party, pro-EU To Potami, on Thursday pledged to back a new deal between the country and its creditors that could face a rocky ride through parliament.
"Whichever agreement comes to parliament, all To Potami lawmakers will vote for it, without haggling, because the country needs oxygen," party leader Stavros Theodorakis told Skai TV.
To Potami has 17 lawmakers in the 300-seat legislature, and its support would go a long way in securing parliamentary approval.
The leftist-led coalition government has 162 lawmakers, but there are fears that several of its MPs will refuse to back an agreement that includes austerity measures.
The government of Prime Minister Alexis Tsipras has been bargaining with the country's EU-IMF creditors for four months.
Time is running short as Greece may not have enough money to repay earlier loans from the IMF that are due in a series of payments from June 5.
Tsipras on Wednesday said Greece was "close to an agreement" and his Economy Minister Yiorgos Stathakis said negotiations would conclude by Saturday.
Greece's creditors, on the other hand, insist that insufficient progress has been made in the talks to warrant such optimism.
German Finance Minister Wolfgang Schaeuble late on Wednesday expressed surprise, noting that "little progress" had been made in the talks.
"I am always surprised when we are told by Athens that an agreement is imminent," he told German station ARD.