A Tunisian court on Wednesday ordered the release of presidential candidate Nabil Karoui days before the country's run-off presidential election scheduled for Sunday, 13 October.

Karoui, 56, was detained in August before the first round of voting, and has spent the entire campaign period in prison pending a verdict in his trial for money laundering and tax evasion, which he has denied.

The presidential hopeful has been under investigation since 2017. He was placed in pre-trial on August 23.

“The appeals court has decided to immediately free Nabil Karoui." his lawyer Kamal Ben Massoud said.

“His release saved our transition and the situation at the last moment ... We were in a very difficult moment in Tunisia which really threatened Tunisian democracy." Karoui's spokesman Hatem Mliki said.

The Tunisian presidential election is the North African country's second since the 2011 revolution that toppled longtime leader Zine El Abidine Ben Ali.

The polls come following July's death of the nation's first democratically-elected leader, Beji Caid Essebsi.