An opinion poll showed support for the League had risen to 28.5% from 17% at the March 4 election
Italy will no longer be "Europe's refugee camp," newly installed interior minister Matteo Salvini said on Monday as he promised tough action to reduce migrant arrivals and send back those who have already come.
Salvini, head of the right-wing League and a deputy prime minister in the eurosceptic coalition, has made curbing immigration a clarion call of his party whose popularity is rising fast in opinion polls.
Two days after the government was sworn in on Friday, Salvini headed for Sicily, the main port of call for more than 600,000 migrants who have arrived on Italy's shores from north Africa since 2014.
"The party is over," for migrants in Italy, he said, before visiting a so-called "hotspot" or reception centre, in the port of Pozzallo, where boat-borne arrivals are registered, photo-identified and fingerprinted.
The League says the vast majority of migrants in Italy have no right to refugee status, Italy cannot afford to help them and by accepting low pay they worsen the working conditions of Italians.
Salvini kept up the pressure on Monday, saying in a radio interview that Italy "can't be transformed into a refugee camp," and vowing to lobby Italy's partners to obtain more EU assistance to handle the problem.
"It's clear and obvious that Italy has been abandoned, now we have to see facts," Salvini said, when asked about comments from German chancellor Angela Merkel that Europe needs a new approach on immigration.
Salvini, who wants to open a migrant detention and deportation centre in every Italian region, later tweeted: "either Europe gives us a hand in making our country secure, or we will choose other methods."
Italy has become the main route into Europe for economic migrants and asylum seekers, with hundreds of thousands making the perilous crossing from North Africa each year and thousands dying at sea. The other main route, from Turkey to Greece, was largely shut after more than 1 million people arrived in 2015.
After at least 48 migrants were killed at the weekend when their boat sank off Tunisia's coast, Salvini said there was no reason for people to be fleeing Tunisia which was "a free and democratic country".
An opinion poll by the Ipsos agency published on Saturday in daily Corriere della Sera showed support for the League had risen to 28.5% from 17% at the March 4 election.
It now stands just 1.6 points behind its coalition partner, the more left-leaning 5-Star Movement, whose support has slipped slightly since it took 32.7% at the election.
Western Europe's first anti-establishment government, which faces its first confidence vote in the upper house Senate on Tuesday, seems determined to hit the ground running.
5-Star leader Luigi Di Maio, also a deputy prime minister as well as labour and industry minister, pledged on Saturday to overhaul the signature labour reform, known as the "Jobs Act," of the previous centre-left government.