The CEO of the Australian radio station responsible for the prank call to the hospital treating the Duchess of Cambridge has described the suspected suicide of the nurse who took the call as "tragic", but said he is satisfied the presenters have broken no laws.

Rhys Holleran, head of the Austereo network, which owns the radio station 2Day FM, said on Saturday the presenters could not have "reasonably foreseen" the events which unfolded.