Playing havoc was perhaps overstating things but the Japanese were on such a shoestring budget logistically that almost any interuption to their supply line would soon become catastrophic. Anything that delays the Japanese increases the chance that Malaya can withstand the initial Japanese assault. Though the Commanwealth would have to be able to keep the sky neutral.
I've never forgoten an interview with a presumably junior member of commanding generals staff on World at War. He claimed that they were so short of food and ammunition he thought Percival was coming to ask for their surrender, not to offer his. You don't have to do all that much for the Japanese to be unable to take Singapore when they did.
Now if the Dutch East Indies fall then Singapore becomes indefensible. If Force Z or any of its surviving capital units (and as its ment to have been enlarged so there should,be some) joins up with the Dutch and refugee American in the Java Sea then at least initially the Japanese attempt to land in Java should be defeated for the time being anyway. The Japanese would return seeking their decisive engagement with their maim fleet. How that would turn out depends on what if any reinforcements the ABDA have recieved, particularly inthe air.