The Maltese armed forces could not have acted any differently in the way they dealt with the five Eritrean migrants last week, given that international maritime law does not cover cases in which people refuse rescue, according to a leading expert in this area.

There are simply no legal provisions describing this scenario, said Patricia Mallia, who heads the University's International Law Department and whose doctoral dissertation deals with migrant smuggling.

"If they were not in distress, we did not need to take them forcibly on our own vessel," she said, adding that the claim that the migrants refused to be rescued seemed to indicate they were never really in distress.

Her statement comes as Italian media reported that a Sicilian Magisterial inquiry is contemplating a criminal case against the crew of an Armed Forces Patrol boat.

Last week, the crew re-fuelled a stranded rubber dinghy carrying illegal immigrants, gave them food and lifejackets and monitored the rest of their journey towards Lampedusa.

The migrants were then picked up by the Italian Guardia di Finanza claiming that more than 70 people who were aboard with them had died during a 20-day journey from the Libyan coast.

The armed forces commander, Brigadier Carmel Vassallo, has insisted that his men did not break any law in taking the action they did as the immigrants did not want to be rescued.

Casting doubt on the immigrants' story that they had been at sea for so long, he said the five migrants were relatively fresh and their dinghy in very good condition.

The Brigadier also said that since being in distress meant in "imminent danger of dying", the Maltese armed forces simply had no right to bring these migrants to Malta unless the migrants asked them to.

This explanation, however, did not satisfy the Italian government which has been berating the Maltese authorities over the incident.

The latest statements came from the influential MP Margherita Boniver, from the governing People of Freedom Party, who said the island had breached human rights and dumped its responsibilities on Italy.

The government denied this and the views of legal experts sought by The Times corroborates this position.

Given the gap in the law, Dr Mallia believes the army had no other course of action to follow in this case.

She also pointed out that while the threat of loss of life was what normally defined a vessel in distress, the state of a boat could change from one moment to the next. This made the monitoring of the boat until it was taken over by the Italian authorities very important.

But the issue becomes more complicated due to a legal distinction between a vessel that is in distress and needs rescuing and one which is not seaworthy, Dr Mallia pointed out.

In her dissertation, she underscored that lack of seaworthiness alone did not necessarily amount to distress. It is only when the vessel's lack of seaworthiness poses a threat to human life that the people on board have to be rescued.

Human rights expert Neil Falzon agreed that there is a lacuna in this area but said that in the absence of an international definition of what amounts to distress, migrants should only be allowed to continue with their journey if it is certain they will make it to their destination.

"Given the immediate and serious risks of such a journey, personally I don't believe it's a wise decision to let them continue with their journey," he said.

Dr Falzon, who used to head the local office of the UN High Commission for Refugees, said it was up to the captain of a boat to decide whether the people on board needed to be rescued. However, it was unclear how this applied to refugees crossing the sea, who had no captain and were travelling in an unflagged vessel.

"In that case, it is the rescuing boat which has to make that decision," he said.

UNHCR spokesman Laura Boldrini believes that migrants who end up without fuel in the middle of the Mediterranean have to be rescued, however she said the international organisation did not have an official position on this issue.

She was reluctant to discuss last week's case, saying that an investigation needed to take place, especially since there were conflicting versions.

In fact, Brigadier Vassallo has disputed the migrants' claim that 73 people on board the vessel had died, saying that there was no evidence to suggest this.

Eritreans living in Malta and other European countries, possibly related to the victims, had sent an e-mail to alert the Maltese authorities that a boat carrying around 80 migrants had left from Libya on July 29 but had not reached any destination.

The army's description of the immigrants' state of well-being seems to be corroborated by an Italian government doctor who was on the ground when the migrants arrived in Lampedusa on Thursday.

Dr Valeska Padovese told The Sunday Times: "They must be confusing the dates. They arrived in a bad condition but if they were so long at sea they would have never arrived, especially with the August heat."