The Diciotti arrived at Catania late on Monday night, hours after Transport and Infrastructure Minister Danilo Toninelli announced that the port was open to the ship, but has not been allowed to disembark.
The boat spent some four days at sea after picking up 177 people near the southern Italian island of Lampedusa, including an estimated 30 unaccompanied minors.
"The brave men of the coastguard have fulfilled their duty by saving lives barely 17 miles from Lampedusa. Now Europe must quickly play its part," Toninelli tweeted.
Interior Minister Matteo Salvini has threatened to take those rescued to Libya unless other EU countries offer to take them in, despite reports of serious abuses in migrant detention camps in North Africa.
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A spokesperson for the EU's migration commission told Ansa news agency that member states had been approached about the situation and "we are working to find a solution as soon as possible".
"The people aboard have suffered abuse, torture [and are] victims of human trafficking," commented the spokesperson for the UN's refugee agency in Italy, Carlotta Sami. "They urgently need assistance and the right to claim asylum. A fundamental right, not a crime."
According to the latest figures from the UNHCR, the crossing from North Africa to southern Italy is becoming more deadly: more than 1,500 people died making the journey between January and July, or one in every 17 who tried. The death rate tripled this year compared to the same period in 2017, the agency said.