Ange Postecoglou could be made to wait "several weeks" before taking over as Celtic manager.
UEFA have revealed the Yokohama F. Marinos boss does not hold their required Pro Licence coaching badges.
Celtic have appealed for the 55-year-old to be granted an exemption due to his vast 25 years of experience.
But European football's governing body have told The Scottish Sun this could be a slow process, threatening another unwelcome delay as the already protracted search for Neil Lennon's successor approaches 100 days.
It's reported Postecoglou could be granted the exemption on the basis he undertakes the Pro Licence course.
A UEFA spokesperson said: “Mr Postecoglou does not currently hold the UEFA Pro Licence.
“A recognition of competence procedure has been initiated. The process could take several weeks.
"We don’t have any further information to provide at this stage.”
Postecoglou's management career started in 1996 and he spent four years as boss of the Australia national team, including at the 2014 World Cup
His only stint in Europe came in charge of Greek minnows Panachaiki back in 2008.
Celtic are expected to return for pre-season training on June 17 but it appears Postecoglou faces an uphill battle to be present at Lennoxtown for the first day of preparations.
He will be required to isolate for 10 days after arriving in Scotland and the Pro Licence resolution could hold him back further.
It's claimed Gavin Strachan and John Kennedy could lead training until the new manager gets the all-clear.
Celtic begin their Champions League qualifying campaign on July 20 or 21 before the new Premiership campaign kicks off on the weekend of July 31.
