Tanzanian opposition leader Tundu Lissu told a court on Monday he had been denied his basic legal rights and that he would defend himself against a treason charge that carries the death penalty.

The politician, who was detained in April, told a packed courtroom that he had been denied confidential access to his lawyers since his detention.

"All the 68 days they have not been allowed to see me or speak to me," he said.

"It is time to step aside and let me do what I must do. From now on I will be my own lawyer," he said.

Electoral reforms

Lissu has led a forceful charge against the government, vowing his party would not participate in polls without significant electoral reforms.

Wearing a shirt emblazoned with the words "No Reforms, No Election," Lissu told the judge that, despite not being sentenced yet, he has been placed in the prison's death row section.

"I am under constant surveillance by day and night," Lissu said, adding he has also been denied the freedom to worship.

He has been arrested several times in the past, but this is the first time he has faced such a serious charge.

Lissu's party has accused President Samia Suluhu Hassan of returning to the repressive tactics of her predecessor, John Magufuli.

In May, two activists from Kenya and Uganda were detained after travelling to Tanzania in solidarity with the opposition leader, both alleging torture and sexual abuse by the officers who detained them.