Italy said that 4,000 immigrants have reached its shores by boat in the past two days - the highest number since it launched a naval operation to rescue them at sea in the wake of two shipwrecks last year.

"The landings are non-stop and the emergency is increasingly glaring," Interior Minister Angelino Alfano told Rai Uno public radio on Wednesday, adding that a corpse had been found on one of the migrant boats rescued.

Alfano estimated that 15,000 migrants crossing the Mediterranean had been rescued so far this year and said up to 600,000 migrants from Africa and the Middle East were ready to set off from Libyan shores.

He called on the international community to set up "refugee camps" in Libya and said the next six months would be "extremely difficult" because favourable weather conditions meant more would make the crossing.

Italy reported a 60 percent increase in asylum claims last year, according to an AFP news agency report, mainly people fleeing the war in Syria, although the number of arrivals is still lower than in the wake of the Arab Spring revolts in 2011.

"Europe must take the situation in hand. It cannot say that, having given 80 million euros ($110 million) to Frontex, the problem has been resolved," Alfano said, referring to the European Union's border control agency.

Alfano, who is also head of the New Centre-Right party, also said that "the procedure for expelling those who do not have a right to stay in Italy should be sped up, but we should welcome those who have a right to asylum".

The latest increase comes just ahead of European Parliament elections next month and lawmakers from the anti-immigration Northern League, a small opposition party, have been quick to weigh in on the issue.

'Not an invasion'

MPs Davide Caparini and Nicola Molteni released a statement urging Alfano to stop the arrivals "by turning them back" and complained that asylum-seekers were getting better treatment "than any Italian citizen".

However, others affirmed that the situation is not as bad, and blamed Italy for failing to prepare

Senator Luigi Manconi from the centre-left Democratic Party, head of the human rights committee in parliament, said the problem was Italy's own.

"We are not facing an invasion, absolutely not. We have to criticise ourselves for not putting in the necessary measures in time," he said.

The navy said it had rescued around 2,500 migrants of the 4,000 arrivals and that others were being intercepted by merchant ships and coastguard vessels.

Italy began its naval operation "Mare Nostrum" (Our Sea) -- a Latin reference to the Mediterranean -- after more than 400 migrants from Eritrea and Syria perished in twin tragedies off Italian shores in October 2013.

The navy said it has carried out health checks on board and fed the new arrivals, who were taken to the ports of Augusta and Pozzallo in Sicily.

Six large tents were set up in Pozzallo on Wednesday to offer shelter to the migrants when they arrive. Others have already been taken to other parts of the country.