ROME (Reuters) - The leaders of Italy’s right-wing parties have pledged to deport hundreds of thousands of migrants if they win the March 4 parliamentary election, a promise that may win votes but will be hard to keep.

FILE PHOTO: FILE PHOTO: Forza Italia party leader Silvio Berlusconi waves during a rally for the regional elections in Palermo, Italy November 1, 2017. REUTERS/Guglielmo Mangiapane/File Photo/File Photo

A center-right coalition that includes former prime minister Silvio Berlusconi’s Forza Italia (Go Italy!) and the anti-immigrant League is leading in opinion polls, in part because of their hardline on immigration.

Surveys show Italians are increasingly uneasy after more than 600,000 migrants reached Italian shores by boat in four years. At the weekend, a neo-Nazi wounded six migrants in a shooting spree in central Italy, thrusting immigration to the heart of the election campaign.

“These 600,000 people, we will pick them up using police, law enforcement and the military... everyone can help identify them by pointing them out, and they will be picked up,” said Berlusconi on Monday.

“Then we’ll use state ships and airplanes to take them back to their countries of origin,” he said.

League leader Matteo Salvini said irregular migrants would be rounded up and sent home “in 15 minutes” if he and his allies take power.

But the reality is that deportations are expensive, time consuming and complex.

It would take years to repatriate those irregular migrants already living in Italy and thousands continue to arrive each month, mostly by boat from North Africa.

“For many years people have been saying more irregular migrants should be sent home, but in fact it has not been possible,” said Flavio Di Giacomo, a spokesman for the United Nations’ International Organization for Migration in Rome.

MANY HURDLES

Interior Minister Marco Minniti said he wanted to increase expulsions, but deported 6,500 people last year against 5,200 a year earlier.

“If we wanted to repatriate 600,000 irregular migrants, and we could send 200 per working day, it would take more than 15 years,” said Senator Luigi Manconi, a member of the ruling Democratic Party (PD) who next month will take charge of the country’s anti-racism office.

The cost of deportations is high. Forced returns require that migrants be put in detention centers before departure, planes must be chartered and wages paid - two guards for each migrant.

In 2016, the repatriation of 29 Tunisians from Italy cost 115,000 euros ($141,795). On average, repatriations conducted jointly with EU border agency Frontex cost 6,500 euros each, an EU observer study found last year.

Italy has bilateral agreements with 24 non-European countries allowing for returns, but migrants often avoid being identified or countries refuse to recognize them as citizens.

Anis Amri, a Tunisian migrant who mowed down 12 people with a truck at a Berlin Christmas market in December 2016, was to have been deported when freed from an Italian prison in 2015. But Tunisia, with which Italy has a return agreement, did not recognize him as a citizen within the given timeframe, so he was ordered to leave the country and released.

“Throughout history, far-fetched rhetoric takes the place of realism in an election campaign,” Salvatore Fachile, a Rome lawyer who specializes in immigration, said. “There’s nothing realistic about mass deportations.”

Pope Francis urged Catholics on Tuesday to reflect on the causes of violence against migrants during the approaching season of Lent.