The official body stated it was regretful that a mediated or agreed accommodation could not be reached concerning the proposed march organised by the Orange Order.
While acknowledging that the Commission's determination is subject to legal challenge, officials insisted there would be differing opinions on the outcome.
Leadership figures were specifically warned to avoid any public statement or action that might suggest the ruling justifies anything other than peaceful protest.
The government stressed the importance of all parties maintaining respectful and temperate public pronouncements in light of the decision.
Community relations in Portadown have been noted as having improved significantly over recent years.
For further information regarding the matter, the duty press officer can be reached on 028 9037 8110.