The QLD Security of Payment Act provides for interest at s13(2) and s13(3) of the Act as follows:

(2) Subject to subsection (3), interest for a construction contract is payable on the unpaid amoun t of a progress payment that has become payable at the greater of the following rates—
(a) the rate prescribed under the Civil Proceedings Act 2011, section 59(3) for a money order debt;
(b) the rate specified under the contract.

(3) For a construction contract to which Queensland Building Services Authority Act 1991 , section 67P applies because it is a building contract, interest is payable at the penalty rate under that section.

Under s13(2)(a) of the Building and Construction Industry Payments Act 2004 (QLD) the prescribed rate under s59(3) of the Civil Proceedings Act 2011 can be found here.  This provision in turn references the Supreme Court of Queensland Act 1991 Interest Rates.

Under s13(3) the Queensland Building Services Authority Act 1991, section 67P applies.  This provision in turn references the rate comprising the annual rate, as published from time to time by the Reserve Bank of Australia, for 90 day bills (see table titled Interest Rates and Yields – Money Market – Daily – F1 (xls)).