Australia’s beefed-up and opaque foreign investment regime is making it harder to advise  Chinese clients on acquisitions and risks deterring investment, lawyers say.

New laws that took effect at the start of January give regulators more scope to block acquisitions on national security grounds. They also allow the treasurer—the lawmaker who has the final say on foreign acquisitions—to review applications even after a transaction is completed and even if it doesn’t meet the formal criteria for a review.