Mason was pulled over by police in Newcastle on his way to a training session with the NRL club on Monday morning.

A police spokeswoman said a 33-year-old man from Charlestown was stopped for a random breath test and returned a reading of 0.079.

The Knights released a brief statement on their website.

‘‘Willie Mason failed a random breath test on the way to training early this morning,’’ the statement read.

‘‘Mason is due to appear in court on February 20th, 2014 in relation to this charge.

‘‘The club will be making no further comment in relation to this matter.’’

Mason has apologised after adding to a horror off-season for the Knights.

On Monday afternoon he took to Twitter to issue on apology.

‘‘Jus want 2 say sorry to everyone. I take full responsibility it was bad judgment. I thought I was fine 2 drive. Obviously not. sorry again,’’ he wrote.

Mason has been heavily involved in promoting the NRL Nines in New Zealand and Australia in the lead up to the Eden Park event on February 15 and 16. But his involvement in the short-form tournament is now under a cloud with the incident under investigation by the NRL Integrity Unit.

‘‘The NRL Integrity Unit is aware of the incident and will work through the proper processes with Newcastle,’’ an NRL spokesman told AAP.

Mason, a former Australian and NSW representative, has played 256 first-grade games for the Bulldogs, Sydney Roosters, North Queensland Cowboys and the Knights.

The 33-year-old is in his third season with the Knights and has revitalised his career after a series of off-field issues.

The latest incident comes less than a month after fellow Knights prop Russell Packer was jailed for two years for assaulting a man outside a Sydney bar shortly after joining the club on a four-year contract.

New Zealand international Packer, who is appealing against the sentence, had yet to play for the club and was subsequently sacked.

Details also emerged on Sunday of exciting centre Dane Gagai, who joined Newcastle in 2012 after being sacked by Brisbane, going missing at an emerging Queensland Origin camp following a boozy night out.

The 23-year-old had a night out during the January 17-19 camp and didn’t front for training the next day at the camp being run by Knights coach Wayne Bennett at the Queensland Academy of Sport in Brisbane.

Former Knights five-eighth Ben Rogers, who is now employed by the club as a community and charity support manager, was also embroiled in controversy when he was charged with two counts of assault following an incident at a taxi rank late last year.

-with Stephen Ryan, AAP