The American Grammy Award-winning rocker made the poorly received comments that many regarded as racist at a gig in Melbourne on Saturday night.
“What you do is, when you get on the plane on your way here, you start drinking. And then I drink until I think I’m Australian. And I keep drinking until I think I’m a black Australian,” he told the crowd, according to news reports.
After a social media uproar, he took to Facebook to apologise.
“Please understand that although it is no excuse, I was completely unaware that in Australia there is a polarising social issue happening right now involving indigenous people and alcohol,” he said.
“When I was made aware of it, the ground fell out beneath me, and I realised that people may now see me as the exact opposite of who I am.
“I’m sitting here in my hotel room completely gutted that a joke that I made was much more relevant to the times in Australia than I realised. I feel like a fool and apologise to all Australians.”
Aborigines have lived in Australia for at least 40,000 years and number just 670,000 out of a total population of 24 million.
They have long had significantly lower education, employment and life expectancy compared to non-indigenous communities, with drug and alcohol abuse a key problem.
In a further post on Monday, Thomas, who also performs as a solo artist, attempted to explain the “joke”.
“I made a comment about drinking so much on the long flight over that I started to think I was something I’m not,” he said.
When he discovered his comments were seen as offensive, “I sat in my room and I cried”, he said.
“I have seen people comment that after coming here for so long I should know that there is a connection between the indigenous peoples of Australia and a stereotype involving drinking. Embarrassingly, I truly didn’t.”
Matchbox 20 rose to international fame with their debut album Yourself or Someone Like You in 1996.