* Direct contact possible between smugglers, NGOs - prosecutor
* Court has not opened criminal probe - prosecutor
* NGOs strongly deny any ties to traffickers
By Steve Scherer
ROME, March 22 (Reuters) - Humanitarian ships operating off the coast of Libya are undermining the fight against people smugglers and opening a corridor that is ultimately leading to more migrant deaths, an Italian prosecutor said on Wednesday.
The chief prosecutor of the Sicilian port city of Catania, Carmelo Zuccaro, said he suspected there may be direct communication between Libya-based smugglers and members of charity-operated rescue vessels.
Normally Italy's Coast Guard dispatches rescue vessels after receiving distress calls.
"I'm convinced of the fact that it's not always the (Coast Guard) command centre that calls the NGOs," Zuccaro said in testimony to a parliamentary committee on European border issues. He said non-governmental organisation (NGO) contacts are on the Internet, making it possible for anyone to call them.
"So how can you exclude that there have been direct calls? These contacts have not been proven nor excluded," Zuccaro said, adding that it was "worth investigating".
The number of migrants attempting to cross into Europe via the Libya-to-Italy route has increased substantially this year after a deal between the European Union and Turkey largely shut down that route.
Last month the Catania court set up a task force to look into possible financial ties between smugglers and NGOs. Zuccaro said the court so far found no proof of such collusion.
NGOs strongly deny any wrongdoing and say they operate on donations with the sole aim of saving lives.
Most of the record 181,000 boat migrants who came to Italy last year were rescued at sea. Thirty percent of rescues in 2016 were carried out by NGOs who have made 50 percent of this year's rescues amid a surge of arrivals, Zuccaro said.
Zuccaro said NGOs are in effect blocking efforts to fight people smuggling because it is so easy to cross the 12 nautical miles and reach charity vessels waiting just beyond Libyan territorial waters while smugglers can stay on shore, out of reach from authorities.
"They are creating a corridor that opens a completely anomalous path to Italy. It certainly would not exist without them," he said.
The short distance from Libya also means that increasingly flimsy rubber boats are being used for the journey, a factor that makes the journey more deadly.
Deaths on the central Mediterranean route rose to some 4,600 last year from 2,900 the previous year, the International Organization for Migration (IOM) estimates.
"Our aim is to save as many people as possible. It shocks me that there are so many doubts over our work," said Valeria Calandra, Italy's president of SOS Mediterranee.
The NGO's Aquarius ship brought more than 900 rescued migrants to Catania on Tuesday.
Calandra added that SOS had not received any requests for information from the Catania court, but that it would cooperate fully if it did.
Separately, Pope Francis, who has made the need to help migrants one of the planks of his papacy, said on Wednesday: "We must not forget that this problem of refugees and migrants today is the worst tragedy since World War Two." (Reporting by Steve Scherer; Editing by Julia Glover)