Prices for leak detection and repair will vary widely. Of course charges will be lower with your help uncovering the facts, needed to determine the leaks location.
Average charges are $200. Higher prices will be realized for below ground work, however many leaks are fixed within one hour.
Many pools leak in more than one area, so monitoring is important after any repair is made.
There may be additional charges for travel outside the 'Sunshine Coast Area', cutting & replacing concrete and for SCUBA work.