World number 11 Allen, 26, claimed that China's world number 81 Cao Yupeng failed to notify match officials of an illegal push shot while 5-4 up in their World Championship first-round match, which Cao won 10-6.
He went on to claim that Chinese players had cheated against him in the past, and that such behaviour was a "Chinese thing".
The controversial Northern Irishman's latest outburst was called "unacceptable" by World Snooker chairman Barry Hearn, leading to a disciplinary charge against Allen, who has quit Twitter since the incident.
In a statement through his management, On Q Promotions, Allen said: "It is fair to say that this season has been one of ups and downs. The highs of winning my first ranking title and finishing runner-up in the UK Championships have been overshadowed by some ill-judged comments from myself.
"I realise that I need to ensure that my off-table behaviour matches the standard and level of professionalism I set for my on-table etiquette. I will return for the 2012-13 season with an improved approach to giving my opinions publicly.
"I would like to formally apologise to anyone who may have been offended.
"Having taken some time to reflect on my comments I can appreciate that I overstepped the line at a time when I was heavily influenced by the emotions of a disappointing defeat.
"I would like to take this opportunity to apologise to Cao Yupeng if he felt that my comments were insinuating he were a cheat."
Allen has already been fined four times this season, at a cost to him of more than £2,500.
Allen castigated Cao for being guilty of a push shot in the 10th frame. Allen said referee Paul Collier failed to spot the push before proceeding to accuse two more Chinese players of cheating in the past.
"It was a big stage of the match considering I had put him under pressure last night to get back to 5-4. If the referee rightfully calls a foul there, I have a good chance of going 5-5. He (Cao) went on from there to pull away to 7-4," said Allen.
"It seems to be a bit of trait for the Chinese players. There's been a few instances in the past...fouls...and blatant cheating going on. It needs to be corrected because he (Cao) is a good enough player. He doesn't have to do that.
"He did look at the referee as soon as he done it as if to say: 'you're not going to call a foul here?' I looked at Paul and Michaela (Tabb) who was marking the match and Griffiths (former world champion and coach Terry) who was commentating on it. Anything that Terry says, I trust.
"He (Griffiths) pretty much confirmed it at the interval. It is a pretty sad state of snooker if it has to come down to that. Its not the first time. Maybe it is just a Chinese thing."
Allen was fined £1,000 for his criticism of the conditions at China's Haikou World Open last month before apologising. Ironically, Allen won the event.
Allen tweeted: "Dead cat found this morning. Any wonder this place stinks. Must be dead cats all round the town. This place is horrendous. It just baffles me how world snooker continuously go out of their way to put tournaments on in the middle of nowhere. Journey a nightmare. People are ignorant. Place stinks. Arena's rubbish, tables poor, food is horrendous. Other than that I love China."