EU powers under fire as migrant shipwreck horror revealed

European governments came under increasing pressure to tackle the Mediterranean's migrant crisis ahead of an emergency summit, as harrowing details emerged of the fate of hundreds who died in the latest tragedy.

Allegations of callous disregard for Arab and African lives are haunting Europe's politicians as it was revealed that around 800 victims, including an unknown number of children, died in hellish circumstances off the coast of Libya on Sunday.

The migrants had been been locked in the hold or the middle deck of the 20-metre (66-foot) boat, according to survivors, which capsized when it collided with a Portuguese vessel.

UN human rights chief Zeid Ra'ad Al Hussein said the incident had occurred due to a "monumental failure of compassion" by the continent's rulers.

Stung by the full horror of the disaster, the UN Security Council called for a strengthened global response to migration and human trafficking, and the 15-member council voiced support for southern European countries struggling with the refugee influx.

European Commission president Jean-Claude Juncker called for a show of "financial solidarity" towards the countries bearing the brunt of the drama.

Mere "compassionate rhetoric" was not enough, he said during a visit to Austria, whose Chancellor Werner Faymann would like to see massive refugee camps built in North Africa to shelter would-be migrants and refugees.

British Prime Minister David Cameron called for a halt to what he termed the "cargo of death" and the Times reported that Britain was considering sending a warship to help with rescue efforts.

French President Francois Hollande urged Europe "to go much further" in tackling the migrant crisis, and repeated calls for more maritime and aerial surveillance over the Mediterranean.

- Boat captain charged -

 Prosecutors in the Sicilian city of Catania said Tuesday they believed the boat's Tunisian captain was responsible for steering mistakes and the reckless overcrowding which led to disaster.

Mohammed Ali Malek, 27, will appear before a judge on Friday along with crew member and Syrian national Mahmud Bikhit, 25, who was also arrested following the catastrophe.

He was questioned by investigators Tuesday after being arrested on suspicion of culpable homicide, causing a shipwreck and aiding illegal immigration. Bikhit faces potential charges on the latter count.

Italian Prime Minister Matteo Renzi described the traffickers who packed their human cargo into the boat as akin to 18th-century slave traders.

Prosecutors said the survivors had told them how they had been held for up to a month in disused factories in Libya before being packed onto the boat.

One man was beaten severely with sticks as punishment from moving away from the group to answer the call of nature, according to a survivor's statement.

Most of the survivors and the victims appear to have been young men but there were also several children aged between 10 and 12, said Carlotta Sami, spokeswoman for the UN High Commissioner for Refugees.

"We have not yet been able to ask them about this but it seems certain that many of them will have had friends and family who were lost in the wreck."

At talks in Luxembourg on Monday, EU ministers agreed on a 10-point plan to double the resources available to maritime border patrol mission Triton and further measures will be discussed on Thursday.

Critics say Triton is woefully inadequate and are demanding the restoration of a much bigger Italian operation suspended last year because of cost constraints.

The survivors, who hailed from Mali, Gambia, Senegal, Somalia, Eritrea and Bangladesh, were all recovering Tuesday at holding centres near Catania on Sicily's eastern coast.

Sunday's disaster was the worst in a series of migrant shipwrecks that have claimed more than 1,750 lives this year -- 30 times higher than the same period in 2014 -- and nearly 5,000 since the start of last year.

If current trends continue, there could be 30,000 deaths at sea this year, the International Organization for Migration (IOM) warned.

Italian officials believe there could be up to one million more would-be immigrants to Europe waiting to board boats in conflict-torn Libya.

Many of them are refugees from Syria's civil war or persecution in places like Eritrea. Others are seeking to escape poverty and hunger in Africa and south Asia and secure a better future in Europe.

- Australian example -

Despite the prospect of further loss of life, a number of other EU governments remain reluctant to expand search-and-rescue operations, arguing that they only encourage migrants to attempt the crossing.

Australian Prime Minister Tony Abbott said Europe should follow his government's lead by deploying military forces to turn migrant boats back.

"The only way you can stop the deaths is in fact to stop the boats," Abbott said.

Australia's policy has drastically reduced the number of asylum-seekers arriving on its soil and deaths at sea but has been attacked as undermining the principle of asylum.

Ideas being looked at by the EU including trying to capture or destroy people-smuggling boats and a pilot scheme for the fast-track return of migrants to their home countries.