IMAGE - Getty Images

Ben Barba has failed to have his 12-match rugby league ban overturned, cruelling his chances of playing for St Helens until August.

The 2014 Super League champions signed the 28-year-old Australian on a two-and-a-half-year contract just over a month ago after taking advantage of the amended marquee player rule introduced by clubs earlier in the year.

However, Barba arrived via French rugby union club Toulon with a hefty suspension hanging over him after he tested positive for cocaine during Cronulla's NRL Premiership celebrations.

The Rugby Football League decided to honour the ban imposed by the NRL and an independent operational rules tribunal, sitting in Leeds on Tuesday evening, dismissed Saints' appeal.

"The independent panel, led by Judge Peter Charlesworth, confirmed the suspension originally set by the NRL and subsequently recognised by the Rugby Football League, should remain," the statement read.

Barba has already sat out five games and will now be available for round four of the Super 8s in the week beginning Monday, August 28.

St Helens argued that, had the player been caught using cocaine in an out-of-competition test in England, he would have avoided a ban.

The RFL had to weigh that up against loyalty to their NRL counterparts, who could have been expected to receive their backing.

The governing body were loathe to be seen to be undermining the authority of the NRL, who insisted the player would still have to serve his 12-match ban if and when he returns to Australia if he was allowed to by-pass it in Super League.

- AAP