Britain, a strong supporter of the insurgency in Syria, is the most outspoken proponent of relaxing the arms embargo but faces strong opposition from several members that say more weapons would only increase the killings and tarnish the EU's reputation as a peace broker.
German Foreign Minister Guido Westerwelle said it was not clear if the EU foreign ministers, meeting in Brussels, would reach an agreement on the issue.
"The positions are far apart," he said on Monday.
As the Syrian government struggles with the more than two-year old bloody war, the US, Israel, Britain and some of their Western allies have already threatened to send more arms to militants if President Bashar al-Assad does not leave his post.
Assad, who has vowed to stand by his people and support them to end the foreign-backed violence, has said any decision about the future of Syria lies at the hands of Syrian people and no other side can interfere in Syria’s affairs.
Reports of divisions among EU leaders came as the Syria's opposition is discussing a decision on joining President Assad's government at a peace conference in Geneva next month.
Syria's foreign minister confirmed on Sunday that the government would attend the summit "in principle".
Members of the main opposition side are currently meeting in the Turkish city of Istanbul to decide whether to attend the conference.
However, the date, agenda and list of participants for the so-called Geneva 2 conference remain unclear, and wide gaps persist about its objectives.