A member of the armed forces has performed a citizen's arrest after being the victim of a road rage altercation in Melbourne’s west this morning.

Police said the 51-year-old man from was cut off by a driver with distinctive red hair, who was driving erratically on Point Cook Road, Altona Meadows, just before 10.30am.

Both men turned into the Sanctuary Lakes Shopping Centre car park and exchanged words.

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The armed forces member pinned the alleged offender down. (3AW)

Police allege the man with red hair assaulted the member of the armed forces.

But then the tables were turned, as the soldier carried out a citizen’s arrest by sitting on the man until police arrived.

Witnesses described seeing three police cars pull up and the alleged offender was placed into handcuffs.

Police have praised the actions of the member of the armed forces, who based locally, for protecting other people in the area.

The incident unfolded outside Sanctuary Lakes Shopping Centre car park. (3AW)

9NEWS has been told had it not been for his actions, other people may have been hurt.

Paramedics were called and treated the alleged offender who was seen bleeding from his head.

The armed forces member, who police say was trying to keep the matter low key, was uninjured and will not face any charges.

A photograph of the scene sent to 3AW's Neil Mitchell program show the armed forces member sitting on the alleged offender in the car park in full view of shoppers.