An in-principal agreement was made with the Rugby League Players' Association in December.
But players from four clubs have yet to sign off on the deal, in which the salary cap will rise from $4.4 to $5.8million for the 2013 season.
Mattiske ends his eventful seven-month stint in the hotseat tomorrow when Dave Smith takes over but says he expects to rubber stamp the new deal with the RLPA within days.
The league's leading players, including Melbourne Storm premiership captain Cameron Smith, have lobbied for a new pay deal with the game's top decision makers.