The NRL is offloading thousands of free tickets to its non-Sydney grand final in a bid to fill the 83,000-capacity ANZ Stadium for Sunday's season-ending showdown.

With out-of-towners Melbourne and North Queensland contesting the decider, ticket sales have been much softer than usual, with the league turning to Sydney juniors as the answer to fleshing out the grand final crowd.

An NRL spokesperson strongly denied up to 20,000 tickets were being handed out, as some industry insiders suggested on Wednesday, claiming the figure was only a few thousand. In any event, the match is not expected to sell out.

The league is using its PlayNRL Rewards system to facilitate the junior ticket handout. An email went out to select junior clubs earlier this week, encouraging players and volunteers to redeem their free grand final ticket from 9am Wednesday morning. A different password was sent out in each email, with the password needed to redeem the free tickets.