Nnamdi Kanu's lawyer says two doctors have been selected to visit the detained IPOB leader.
Aloy Ejimakor, special counsel to Nnamdi Kanu, has appealed to President Bola Tinubu to prevail on the State Security Service (SSS) to allow Mr Kanu to seek independent medical care.
Mr Ejimakor, who made the appeal on a post via his verified Twitter handle on Wednesday, said that Mr Kanu, the leader of the outlawed Indigenous People of Biafra (IPOB), needs urgent medical care, particularly for his ear.
"Dear President Tinubu: Few days ago, I passionately urged you to release Mazi Nnamdi Kanu. You haven't.
"Today, I respectfully urge you to direct the SSS to immediately permit Mazi Nnamdi Kanu the freewill to seek independent medical care, particularly for the ear surgery he needs as of now," he wrote.
The lawyer, in an earlier tweet, claimed he had gone "through so much trouble to advance the cause of arranging proper medical care" for the IPOB leader, but that the SSS did not allow that to happen.
He attached a copy of a letter to the tweet. The letter was signed by the lawyer.
The letter, dated 6 June and addressed to the director-general of the SSS, was in response to a medical report of Mr Kanu believed to have been made by the SSS medical unit.
"This letter serves as a formal introduction as well as an accreditation for the two doctors who have been selected by the Kanu family to examine Mazi Nnamdi Kanu's medical records/report generated by the SSS medical unit," Mr Ejimakor wrote in the letter.
The lawyer identified the medical doctors as Uche Ukwuije, a consultant Otolaryngologist and David Ukoha, a family physician.
The doctors were scheduled to be at the SSS headquarters at 2 p.m. the same day in the company of Mr Kanu's brother, Emmanuel, according to the letter.
"Onyendu (Kanu) must get the proper medical care that he needs from physicians of his own choice," Mr Ejimakor said in apparent frustration, indicating that the move was rebuffed by the SSS.
Mr Kanu was first arrested in 2015 under the administration of former Nigerian President, Muhammadu Buhari.
The IPOB leader was later granted bail in April 2017. He fled the country after an invasion of his home in Afara-Ukwu, near Umuahia, Abia State, by the Nigerian military in September of that year.
He was re-arrested in Kenya and brought back to Nigeria in June 2021, about four years after he fled the country.
The Court of Appeal, Abuja, on 13 October, held that the IPOB leader was extra-ordinarily renditioned to Nigeria and that the action was a flagrant violation of the country's extradition treaty and also a breach of his fundamental human rights.
But the government refused to release the IPOB leader insisting that he (Kanu) could be unavailable in subsequent court proceedings if released and that his release would cause insecurity in the South-east.
The government, through the office of the Attorney-General of the Federation, later appealed the court ruling and subsequently obtained an order staying the execution of the court judgement at the Supreme Court.
The Supreme Court is yet to rule on the substantive appeal by the government.