The one-off reintroduction of betting on the National Youth Competition means bookmakers will be allowed to offer markets on the under-20s showpiece between Parramatta and Manly.

League Central cracked down on a number of exotic betting options offered on NRL matches and outlawed all wagering on underage matches.

The scrapping of betting on on Holden Cup games was a particularly strong stance taken by the NRL, fearful punters could be fed information from figures privy to late team changes that can dramatically reshape markets.

But the NRL has rubber stamped a number of betting options for the decider, including head-to-head on half-time and full-time scores, line betting and total match points over and under a set figure. It will also allow wagering on the first try-scorer.

The NRL said it will be monitoring activity closely through betting monitors and the integrity agreements remain the same as the NRL grand final.

Manly's NYC side has emulated the fairytale run of the NRL's Cowboys, charging into the grand final from eighth spot after their upset win over the Dragons in last weekend's preliminary final.

They will start as outsiders against the Luke Burt-coached Eels, who thumped their western Sydney rivals Penrith in the other grand-final qualifier.

The NRL's strong integrity stance came before former Tigers centre Tim Simona was banned indefinitely for placing bets against his team and on opposition players to score.