Italy and Tunisia were pressed on Thursday to clear hundreds of containers of waste illegally shipped and stored at a port in the North African county.
In the summer of 2020, Tunisian customs officials seized 282 containers that had been shipped from Italy and declared as carrying plastic scrap for industrial recycling.
But the containers were found to comprise a mix of household waste which is barred from import under Tunisian law.
Authorities in Rome had given the Italian firm that sold the refuse, Sviluppo Risorse Ambientali SRL, 90 days to retrieve the cargo from December 9, but the deadline passed without it doing so, said Jabbeur Ghnimi, a spokesman for a court in the Mediterranean port city of Sousse.
Tunisian conservation groups criticised the inaction.
"Tunisian and Italian authorities are showing no determination whatsoever for the return of this waste. Their laxity is inadmissible," said Hamdi Chebaane of Tunisia Verte.
Chebaane, who is also a waste management expert, said a protest is due to be held Sunday outside the port of Sousse.
The waste scandal saw the sacking in December of former Tunisian environment minister Mustapha Aroui and the arrest of people, including customs officials.
In total 26 suspects, including Aroui, are facing prosecution, according to Ghnimi, including the manager of the Tunisian import firm who is at large.
Tunisia accuses the Italian company of failing to meet the deadline to remove the containers from Sousse.
"Tunisian authorities are deploying huge diplomatic efforts to find an amicable solution as soon as possible... but it is the Italian company that is slacking," said Ali Abbes who is handling the case for Tunisia.
The case shines a spotlight on the global trade in waste, which has grown despite stricter regulations aimed at preventing rich countries from dumping their hazardous refuse on poorer countries.
The global waste trade has been growing as more highly industrialised and urbanised countries get rid of their garbage in developing countries.
Interpol warned in August 2020 that criminal organisations have profited from an "overwhelming" surge in illegal waste shipments, particularly to Asia but also other parts of the world.
The garbage often ends up in countries that are ill-equipped to cope with it and endure heavy pollution when waste is burned and dumped in landfills instead of being recycled.
Tunisia does not have the proper infrastructure to treat the waste.