Italy's investigators are ramping up their efforts to stop organised criminal gangs — including the mafia — from smuggling people into the country, in the face of record asylum seeker arrivals.

Key points: In 2015 180,746 people arrived in Italy seeking asylum — up 17 per cent on 2016

In 2015 180,746 people arrived in Italy seeking asylum — up 17 per cent on 2016 More than 5,000 people drowned in the Mediterranean fleeing to Europe

More than 5,000 people drowned in the Mediterranean fleeing to Europe Experts find people smugglers are profiting from the tragedy, exploiting genuine asylum seekers

The number of people who made the hazardous boat journey across Mediterranean Sea from Africa to Italy increased by 17 per cent in 2016.

A record-breaking 180,746 people arrived in the Italian regions of Sicily, Calabria, Apulia and Campania, up from 153,842 in 2015.

Dr Gery Ferrara — the lead anti-mafia prosecutor responsible for investigating the criminal networks that smuggle people to Italy — said authorities started tracking people smugglers as soon as asylum seekers disembarked.

"We try to immediately separate the people who can provide useful information and the possible accused," he said.

"We interview them immediately and try to get evidence.

"We start to collect phone numbers, emails and anything we can that will help the investigation."

Language barrier a hurdle for investigators

2016 was the most deadly year on record, with more than 5,000 people drowning in the Mediterranean while attempting the dangerous crossing to Europe.

The United Nations refugee agency, UNHCR, reported the majority of refugees and migrants came from Nigeria, Eritrea and Guinea.

Half a million asylum seekers have arrived in Italy since 2014. ( Reuters: Guglielmo Mangiapane; file photo )

Dr Ferrara said the language barrier is the first problem for him and his colleagues.

"This is one of the most relevant problems because we are talking about people that come from all over Africa. They talk different dialects, such as Tigre, so it's a problem."

More than half a million asylum seekers have arrived in Italy since January 2014.

The increase in the number of sea arrivals has put a strain on Italy's anti-mafia division.

"We deal with the trafficking of human beings, a criminal organisation aimed at smuggling migrants, but I also have ordinary mafia crime like murders, like extortion, drug trafficking, fraud, political corruption," Dr Ferrara said.

Mafia profiting from tragedy

The investigations, led by Dr Ferrara, have pieced together a sophisticated and coordinated network of smugglers that stretches from Africa into the heart of northern Europe, as far as the United Kingdom.

The Italian courts have found this group of criminals to be responsible for two shipwrecks in October 2013, where more than 350 people lost their lives.

Anti-mafia prosecutors gather to announce the arrest of people smugglers in Italy. ( ABC: Connie Agius )

Dr Ferrara's investigations have also revealed that the Sicilian mafia, also known as Cosa Nostra, have profited from the refugee crisis.

"Traditional criminal organisations such as Cosa Nostra are trying to infiltrate the sector of the public money, used for the accommodation for migrants, the logistics, the reception centres," he said.

"I can't say too much about this because we are at the beginning of this investigation."

Dr Ferrara has shared the intelligence gathered through his investigations with international counterparts.

"They realise that this isn't just a southern European problem," he said.

"I personally called for many coordination meetings at [European organised crime unit] Eurojust to try to explain to the other countries, especially northern Europe countries, that not only were they the final destination of these people, but also they have people responsible for the crimes of smuggling of migrants and people in their country.

"We have evidence involving their countries that we provided during these meetings and from this material they are starting their investigations."

He said the soaring number of deaths had taken a personal toll.

"This phenomenon of the smuggling of migrants in such high numbers and also with the death of so many people is something that of course is affecting me, even if I think that the best thing to do your job is always to try to be very detached from your emotional feelings," he said.