The two sides hurled abuses at each other after a march by student activists from Thammasat University although police were deployed to keep order.
About 500 students and other activists joined the rally at the Tha Prah Chan campus.
After the group reached the Democracy Monument, pro-junta group comprising at least 4 people appeared and cursed the NDM group.
Some of the NDM's participants approached the pro-junta group and the scuffle began. However, the police quickly stopped the incident.