Patrick Hickey should be returned home from Brazil to Ireland otherwise his health could be seriously affected, it was claimed at the start of the 45th European Olympic Committees General Assembly here today.
The Irishman has been held in Rio de Janeiro since August 17 when he was arrested following allegations that he was involved in the illegal sale of tickets for the Olympic Games.
He had his passport confiscated and is unable to leave the country.
Hickey temporarily stood down from his role as President of the EOC following his arrest and has reportedly been charged with criminal organisation, ticket touting, ambush marketing, larceny, money laundering and tax evasion.
The 71-year-old could face up to seven years in jail if he is found guilty.
He has denied all the charges.
"We have studied the allegations against Patrick Hickey and from what we know he is not guilty of any criminal offence," Janez Kocijančič, the acting President of the EOC, told delegates.
"He should enjoy the privilege, which is also part of basic human rights, that he should be able to prove his innocence."
Hickey was taken to hospital complaining of heart problems following his arrest in Rio de Janeiro and spent two days there before being transferred to the notorious Bangu Prison.
He was held there for 10 days before being released, although he is still banned from leaving Brazil.
"Patrick Hickey is not in the best health, his health is deteriorating," said Kocijančič.
"He has has problems with the heart.
"He needs heart surgery and doctors think he should be treated in Ireland.
"Our wish is that the authorities take this health situation very seriously and will allow him to come back to Ireland."
During the General Assembly, a slide was flashed onto the big screen of Hickey with the message: "The warmest wish is that...he can return to his family and Olympic duties as soon as possible".
Earlier, Belarus President Alexander Lukashenko had also offered his support to Hickey when opening the General Assembly.
"Unfortunately, we do not have our EOC President Patrick Hickey with us here today," Lukashenko, who is also President of the National Olympic Committee of the Republic of Belarus, said.
"It is very important for him to feel our support and solidarity.
"There is no proof of any of these horrible accusations."
Kevin Mallon, the director of THG Sports, the company owned by Britain's Marcus Evans and who Hickey is accused of supplying Rio 2016 tickets too illegally, is also facing charges of ticket-touting, illicit marketing and money-laundering in Brazil.
He has also denied the allegation.