Earlier, Hugo Chavez, the Venezuelan president, described the new currency as a "revolution of paradigms".
"The sucre is born in the Alba," Chavez said ahead of the meeting.
"The sucre - an autonomous and sovereign monetary system that will be agreed upon today so that it can be implemented in 2010."
The Alba leaders were also expected to discuss climate change and trade issues during the summit, as well as renew their criticism of the June coup in Honduras.
The coup forced Manuel Zelaya from office on the same day that he planned to hold a non-binding referendum on changes to the Honduran constitution.
"They have shown their claws again in Honduras and overthrown a legitimate, democratic and progressive government; an ALBA government of the Bolivarian Alliance," Venezuela's Chavez said.
"And they aim for legitimacy before a world community that does not recognise them. The coup in Honduras will be defeated, history will defeat them, they are already defeated."
Zelaya's overthrow was roundly criticised by Latin American countries, including Alba members, and the US.
Talks to resolve the political crisis in Honduras are continuing.