A man in his 30s was slashed in the face as the annual pilgrimage to Croagh Patrick took place last Sunday at 1.30pm.
Two carpet blade knives and a pickaxe handle were recovered from the scene.
The man from Dublin was treated at Mayo General Hospital and was later discharged.
Gardaí are following a definite line of enquiry into the incident.
If anyone has any information contact Westport Garda Station on 098 25555.
