The two pharmaceutical giants in December said they would combine their consumer health businesses in a joint venture that would be 68 percent-owned by GSK.

The Australian Competition and Consumer Commission (ACCC) said products produced and sold by GSK and Pfizer in Australia would face strong competition from other players.

For example, GSK's well-known pain management product - Panadol - would face strong competition from Reckitt Benckiser's Nurofen.

"Also, the combined businesses would continue to face competition from the range of generic options available to consumers ... and are usually much cheaper," ACCC Commissioner Roger Featherston said in a statement.

(Reporting by Nikhil Kurian Nainan in Bengaluru; Editing by Stephen Coates)