Former Greens leader Bob Brown has been barred from entering Rwanda, with his travel visa revoked at the last minute.
The former Tasmanian senator said he was scheduled to fly to the central African nation on Monday to offer international support for the persecuted local Democratic Green Party.
But on Sunday he received an email stating that his visa, granted in late October, had been cancelled because of "contradictory messages" in his application.
Dr Brown said it was further evidence that the government of Rwandan President Paul Kagame was restricting democracy and crushing political opposition.
"The government doesn't really want me in the country as a person who comes from a functioning democracy."
Dr Brown agreed to visit Rwanda to support the struggling party - which was banned from the 2010 election there - after meeting its leader Frank Habineza in Senegal this year.
Mr Habineza was arrested and went into exile in Sweden in 2009 after a Greens Party meeting was violently broken up by men wielding sticks, Dr Brown said
Later, the party's deputy leader was found dead, nearly decapitated.
Mr Brown raised his concerns about the political situation in Rwanda when he met the country's foreign affairs minister Louise Mushikiwabo in 2010 during a Commonwealth Heads of Government Meeting in Australia.
He also flagged his intention to visit Rwanda and has written to Ms Mushikiwabo many times since but hasn't received a reply.
"It's not as if they've had no connection with me," he said.
"They've had weeks to consider my visa application."
Dr Brown has notified Foreign Minister Bob Carr of the cancellation.
© 2012 AAP