Those with a view on Seven West Media's acquisition of Perth's Sunday Times have been given an extra week to argue their case.

The Australian Competition and Consumer Commission has deferred a decision on the acquisition of the Sunday newspaper and its PerthNow website from News Corp Australia to August 4.

As in the case of Queensland - where APN News & Media has agreed to sell its NSW/Qld regional newspapers back to News Corp Australia - and New Zealand, with a proposed merger of APN's NZME operation to Fairfax, the outcome would create effective "one-publisher' dominance of the market. The Queensland and New Zealand proposals are also being considered by regulators.

Seven West Media owns Channel Seven and the West Australian, and would gain production and personnel efficiencies from the deal, and would share content under a four-year agreement.