Police say action is expected over a one-punch attack on a year seven student in NSW's Riverina, which was filmed by another student.

The footage shows the 12-year-old boy falling to the ground after a single unexpected punch from another boy at Wagga Wagga High School on Monday afternoon.

After the hit, the boy struggles to stand, and slowly falls to one side, hitting the concrete.

No-one intervenes as he lies unconscious.

NSW Education Minister Rob Stokes called the attack "cowardly".

"I was sickened and appalled," he said.

"This is unacceptable conduct within a school as it is unacceptable conduct anywhere in New South Wales."

Mr Stokes said he had been in contact with Wagga Wagga High School's principal and was "grateful" that immediate disciplinary action had been taken.

Wagga Wagga police told the ABC the victim did not sustain any lasting physical injuries from the attack and was not in hospital.

Family asks for privacy

A school and NSW Education Department spokesperson said the school told the police about the attack on Monday.

"Any student who is found to have participated in an offence that puts at risk the safety of another student will be dealt with decisively through their school's discipline code, and if warranted, face further criminal charges," the spokesperson said.

"NSW public schools have a zero tolerance policy toward violence.

"Schools are a place of learning, where both staff and students have the right to feel safe.

"The main priority now is the care and recovery of the victim, whose family has asked for privacy."

Police said the victim had made a statement and there was enough footage to take action against the other juvenile, believed to be a 14-year-old boy.