Student activists scuffled with riot police in central Myanmar Tuesday, vowing to burst through a wall of security personnel who have surrounded them for over a week at a protest for education reform.

Activists removed barbed wire barricades and tried to push through tightly packed lines of police, according to an AFP reporter at the scene, just days after Myanmar authorities cracked down on a supporting rally in the main city of Yangon.

Student protesters have embarked on months of demonstrations calling for education reform, but plans by a core group to march to Yangon have been halted by police in the dusty central town of Letpadan, who have surrounded around 150 activists since March 2.

Demonstrators told AFP early Tuesday that patience had frayed after authorities appeared to have reneged on an agreement to allow them to continue their march.

"If it isn't going to go as we agreed, we will break the blockade," activist Nanda Sit Aung said ahead of the altercation.

"They will choose whether they allow or arrest us," he said, adding their protest was peaceful and had been long announced to authorities.

The government has defended its Friday crackdown on an unauthorised rally in the heart of the commercial hub of Yangon, despite accusations from witnesses and campaigners that police and men in civilian clothes beat unarmed protesters with batons.

Eight activists were briefly held in the police action, which caused a ripple of outrage in a country where students activism is a potent political force.

Young campaigners have been at the forefront of several major uprisings, including a huge 1988 demonstration that prompted a bloody military assault under the former junta.

Observers fear democratic reforms in Myanmar, which is gradually emerging from decades of authoritarian rule, are stalling in the run-up to a breakthrough general election slated for the end of this year.

The latest crackdown has deepened concerns that authorities have not lost the repressive reflex forged during the junta era.