Cyprus President Demetris Christofias told a public inquiry Monday he was never told of the risk posed by an arms cache that blew up in July killing 13 people and wrecking the island's main power plant.

But the president, who faced almost daily demonstrations for his resignation after the massive explosion at a naval base on the island's south coast, acknowledged that "indirectly" he was responsible for his ministers' errors.

"It is clear in my understanding that the whole incident is down to a failure in the system, a failure of operations and systemic processes that over the decades were not based on principles of meritocracy or good governance," Christofias said.

He said the state functioned without proper checks and balances which spawned "negligence, procrastination and a fear of taking responsibility".

Christofias said that at no point was he informed of the risks posed by the 98 containers of seized Iranian munitions stored out in the open at the Zygi naval base, even after officials met a week before the July 11 blast to discuss their deterioration in the scorching summer heat.

"Unfortunately, the facts show that officials underestimated the risk the cargo posed," he said.

"I asked for the containers to be kept in a safe place, I was told there was a safe place... If I knew they were next to a power station, I would not have agreed they be placed there," he added.

Although Christofias did not accept personal responsibility, he conceded: "Indirectly, I have logical and institutional responsibility for the errors and omissions of my ministers."

The defence and foreign ministers and the commander of the National Guard resigned over the blast. The deputy commander was sacked.

The containers had been at the base since their seizure in February 2009 when Cyprus intercepted a Cypriot-flagged freighter bound from Iran for Syria, under pressure from the United States and other Western governments.

Christofias said the decision to keep the weapons on the island was the "correct" one after a proposal for the UN to take responsibility for the cache did not materialise.

The arms were seized after a UN sanctions committee said the consignment contravened a ban on Iranian arms shipments.