The Treasury has cast doubt on the competition regulator’s claims that companies are wilfully failing to notify it of acquisitions, as the government mulls an overhaul of merger laws that could force firms to fight for approval in the Federal Court.

The Australian Competition and Consumer Commission’s push for more powers is not a done deal, according to a new Treasury consultation paper that floats three options to overhaul merger laws, including a US-style proposal that would greatly curb the regulator’s powers.