The Briton broke his collarbone while training at his home in Essex last week.
Despite requiring surgery Dowsett remained upbeat about his attempt at the record which was scheduled for 27 February.
However slow recovery has forced him to postpone the attempt.
"I'm really gutted this has happened," says Dowsett.
"I've never worked harder for anything and to make this difficult decision with the team and lose this opportunity is a real blow. The positive is that it is a record attempt so we will be attempting it at a later date. I'll now recover properly and be back to full fitness for the road season and another crack at the 'perfect hour.'"
Meanwhile in Australia both Hour Record hopefuls Jack Bobridge and Rohan Dennis are displaying hot form at the Tour Down Under. Bobridge (UniSA-Australia) won the opening stage and led the race for two stages before Dennis took the jersey from him with victory in Stage 3.
Bobridge will make his attempt in Melbourne on 31 January while BMC's Dennis will race at the UCI velodrome in Aigle, Switzerland in February.
Austrian Matthias Brandle holds the current record with a distance of 51.85km.