Flight QZ8501 went down on December 28 in stormy weather with 162 people on board as it flew from the Indonesian city of Surabaya to Singapore.
“Divers have reached the fuselage this morning but they could not get in because there were so many cables and debris,” SB Supriyadi, a rescue agency official coordinating the search told AFP.
He said bad weather later in the day hampered further efforts to check if there were bodies inside.
Rescuers have been trying in vain to reach the main body of the Airbus A320-200 since it was spotted on the seabed by a military vessel last week, but have been rebuffed by difficult conditions.
Officials hope the majority of the victims will be inside the fuselage, and plan a more thorough assessment of the wreckage to determine how to retrieve the bodies.