A failed high court appeal means the company that manufactures Nurofen must pay a $6 million penalty it was handed for misleading consumers with its pain relief range.

The penalty, revised up from an initial $1.7 million, is the highest ever issued for misleading conduct under Australian Consumer Law.

The ACCC accused manufacturer Reckitt Benckiser of false and misleading labelling of its specific pain range.

Nurofen Back Pain, Nurofen Period Pain, and Nurofen Migraine and Tension Headache products were labelled to treat the specific types of pain despite containing the same active ingredient ibuprofen lysine 342mg.