'The two players have been expelled for life from the national team,' Romania coach Victor Piturca said after his side beat San Marino 1-0.
'It's a pity but rules are strict and they should have known it,' he added.
In hot water: Adrian Mutu has been in trouble before for his off-field behaviour
Mutu and Tamas had gone out partying on Monday evening despite strict orders from the coach.
'We understand Piturca's decision,' Mutu said.
Ban: West Brom defender Gabriel Tamas (left)
The expulsions come less than a month before Romania resume their Euro 2012 qualifying campaign against Luxemburg on September 2 and France four days later.
It is not the first time Mutu has found himself in hot water over his off-field lifestyle. He was suspended for taking cocaine in 2004 and still owes over ?15million in damages to Chelsea, his club at the time.
In January 2010 he was banned for nine months by Italian club Fiorentina after he failed anti-doping tests.
When he returned in October, he was involved in a bar brawl and was almost forced to leave Fiorentina during the winter due to his poor attitude in training.
Last month he joined the modest Italian club of Cesena, saying he had come 'to set an example and help the team progress'.
After six qualifiers Romania are currently fourth in Group D, five points behind leaders France.
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