Detained Tunisian presidential candidate Nabil Karoui's inability to campaign is affecting the credibility of the elections and the country's image, interim president Mohamed Ennaceur said on Friday.
Mr Karoui, who will contest a runoff vote against independent Kais Saied on October 13, was detained in August on suspicion of tax evasion and money laundering in a case brought three years ago by a transparency watchdog. Mr Karoui denies any wrongdoing.
"One of the two candidates who won the first round is in prison and does not have the freedom to campaign or speak to his voters," Mr Ennaceur said in a brief televised statement.
"We will continue to ask all officials to find an honourable solution that respects the judiciary to overcome the unusual and strange situation," he said.
Courts have rejected Mr Karoui's plea to be released pending a final verdict four times since his detention.
The independent election commission has said he can contest the election so long as he is not found guilty of a crime.
No final verdict in the case appears imminent, however, and Mr Karoui's continued detention has prompted warnings from local and foreign election monitors that it denies the media mogul a fair playing field in the election.
Tunisia's president has only limited powers, controlling foreign and defence policy, while a prime minister chosen by the parliament manages other portfolios.
Despite being in prison for the first round of the election, Mr Karoui came second out of 26 candidates with 15.6 per cent of the votes, behind law professor Kais Saied with 18.4 per cent.
Mr Ennaceur said he had been in touch with the Justice Minister and the head of the election commission about the situation.
Mr Karoui's unlicensed Nessma TV station has been broadcasting stories critical of the government throughout the election while promoting his philanthropy among poor Tunisians.
Mr Karoui and Mr Saied beat a number of veteran political leaders in what was seen as a rejection of the established forces that have dominated Tunisian politics since President Zine El Abidine Ben Ali was ousted in a 2011 revolution.
Running from behind bars, Mr Karoui has been unable to appear in televised election debates, the first in the country since the end of more than 50 years of autocratic rule, though his wife has been pounding the campaign trail on his behalf.
Constitutional experts in Tunisia have said it is not clear what will happen next. If Mr Karoui loses narrowly, he could have grounds to appeal the result.
If he wins, it is unclear if he could be sworn in unless the judiciary allow him to attend parliament for the ceremony. If he's later found guilty, it's not clear whether he would qualify for presidential immunity for crimes committed before the vote.
A special court, mandated by the 2014 constitution to resolve such controversies, has not yet been set up. Its composition would need to be agreed by both the president and parliament, which has its own election on Sunday.
Meanwhile, further questions over Mr Karoui and his place in the vote were raised this week by reports in regional media that his team had signed a lobbying contract with a Canadian company that may have breached electoral finance rules.
