Facing fierce criticism over his handling of a wave of north Africans landing on the Italian island of Lampedusa, Silvio Berlusconi has put on a vintage display of showmanship, claiming he would empty the island of immigrants within 60 hours, nominate locals for a Nobel peace prize and buy a holiday home there.

So far this year 18,000 north African migrants have sailed to the island, which has only 5,000 native inhabitants.

During a lightning visit to Lampedusa, which is closer to Africa than the Italian mainland, Berlusconi told cheering locals that six chartered ferries were arriving to pick up the remaining 6,000 migrants, mainly young Tunisian men, who have made the sea crossing since the collapse of the Tunisian government in January and the suspension of coastal patrols.

The migrants will join other north Africans who have already been transferred to centres and camps on the mainland after paying out thousands of euros to make the often perilous crossing.

"In 48 to 60 hours, Lampedusa will be inhabited only by Lampedusans," said Berlusconi.

Locals have protested against the nightly arrivals by using fishing boats to block the harbour entrance as the island's immigrant centre was overwhelmed, food supplies ran short and migrants bivouacked on a rubbish-strewn hill overlooking the port.

To frequent applause, Berlusconi told residents he would give them tax breaks and propose they receive the Nobel peace prize for their patience, later telling a press conference he would push for the construction of a casino and a golf course.

"We are buying up the fishing boats so that they cannot be used for the crossings," he said. "That way when I am out of politics I will use them to set up a fresh fish business."

The prime minister also said he would use his private TV channels to promote the relaunch of tourism in Lampedusa. While surfing the internet before his visit, he added, he had purchased a beach house on Lampedusa, which he visited before leaving the island.

A local couple living next door to the €2m house said they had been woken on Tuesday night by noises from the house. "I thought it was the Tunisians," said Rosina Licciardi, "but it was the gardener and his wife cleaning things up."

Berlusconi said he would also ask the mayor to plant a few more trees on the island and paint the houses brighter colours.

Opposition members alleged Berlusconi's appearance was a diversionary tactic as his supporters in parliament worked on a measure trimming the statute of limitations for first-time offenders, a measure they claimed is designed to cancel the prime minister's ongoing trial for bribing British lawyer David Mills.

"Over there he bought a house, while here he bought himself safe conduct," said Pier Luigi Bersani, the head of the opposition Democratic Party.

Berlusconi is now seeking to convince Italy's regional governors to put up the migrants brought ashore. Over 3,000 who have already escaped from makeshift camps have travelled to Ventimiglia seeking to cross into France, where many have relatives.

Interior minister Roberto Maroni has told parliament that a deal was underway with the Tunisian government to take the migrants back.

"If they are economic migrants, and most of them are, then Italy can repatriate," said Laura Boldrini, a UN spokeswoman, "Many come from villages on the coast and worked in the tourism industry but now fear job cuts."

Italy will need to identify each migrant and serve an expulsion order, which can be appealed against, added Boldrini.

Maroni has warned that the Tunisians may be just a warm up for 50,000 migrants fleeing the war in Libya. Boldrini said 1,500 people had crossed to Italy so far from Libya, mainly Eritreans, Ethiopians and Somalis.