There is no precedent in the euro zone to address the debt pile of a bailed-out county and that's why discussions on Greece's debt are taking so long, the Luxembourg finance minister told CNBC.
European institutions and the International Monetary Fund (IMF) have struggled to find an agreement over how to make the Greek debt — which stands at about 180 percent of gross domestic product — more sustainable.
The discussions have dragged since the the current bailout program – Greece's third – started in 2015. However, as the financial assistance to Greece is due to end this August, the country still doesn't know how its future debt payments will be structured.
Speaking to CNBC Thursday, Pierre Gramegna, the finance minister of Luxembourg, said that the reason why the process is taking so long is because this has never happened before.
"We have a post-program surveillance that has been going on for all the countries that were supported and here (Greece) there are some elements that are additional; when something is additional it needs more discussion," Gramegna told CNBC's Joumanna Bercetche.