Kenyan opposition figure Miguna Miguna said he was stranded at Tegel Airport in the German capital, Berlin.
Mr Miguna said he was at the Lufthansa airline lounge in Tegel where he was to board a flight to Frankfurt and then later take another one to Nairobi.
But he said was not allowed to board because there was a red alert on his name.
Kenyan government spokesperson Cyrus Oguna told newsmen that he was not aware of any red alert and was not sure whether it was issued recently or in 2018 when Mr Miguna was deported.
Mr Oguna said that the issue would be resolved by the foreign affairs ministry and told the newspaper that Mr Miguna was still free to travel to Kenya.
Earlier the ministry of interior said in a statement that it would comply with a December 2018 court order that directed the immigration department to issue Mr Miguna with travel documents to facilitate his re-entry to the country.