Approval has been given by Australia's Federal Environment Department for drilling off Ningaloo Reef in Western Australia to explore for gas.
The ABC reports the approval allows Shell Australia to drill an exploration well 50km west of the boundary of the marine park.
The Environment Department says there is unlikely to be any significant impact and no further federal environmental assessment is needed.
The approval includes some specific requirements, including ensuring there are no whales in the vicinity half an hour before a number of processes are undertaken.
Ningaloo Reef is on the world heritage list. The World Wildlife Fund says Federal Environment Minister Tony Burke has failed to protect the reef.