A group of executives from some of Australia’s largest companies who are worried about planned tougher laws to block corporate mergers have taken their concerns directly to Treasurer Jim Chalmers’ department in Canberra.

Companies and their merger advisers are arguing the proposed tougher regulatory approval process for acquisitions that “substantially lessen competition” could lead to deals being delayed, more mergers being vetoed by the competition watchdog and less appeal rights for merger parties.