The 30-year-old was due to check in for treatment at a facility on Easter Monday, but according to new reports, will now be joining his Blue bandmates in Moldova.
"Lee is flying out to earn a few quid," a friend told The Sun.
Lee was arrested last weekend for drink driving and the possession of a class A drug
The singer had promised to seek treatment following his arrest in west London last week.
Lee was arrested in Ealing at 5.30 am on Friday morning after police spotted him driving erratically.
He was initially arrested on suspicion of drink driving, but was also later arrested on suspicion of possessing class A drugs and criminal damage while in custody.
A representative for the singer later issued a statement.
"I can confirm that Lee was arrested in the early hours of Friday morning," it read. "He was arrested on suspicion of drink driving and is awaiting a court date.
Lee is set to travel to Moldova to perform with his Blue bandmates
"He was charged with failure to provide a specimen and criminal damage. A controlled substance was found in his possession.
"This low point has caused considerable concern to Lee’s family, loved ones and of course the Blue boys," it added. "Worried about his recent erratic behaviour, management have now intervened and taken appropriate action.
"No excuses will be made on Lee's behalf, but he will be seeking professional help for those issues that he has been unable to overcome on his own."