Addressing a joint news conference with Manouchehr Mottaki, his Iranian counterpart, in Tehran, al-Moallem ruled out interference in what he called the internal affairs of Lebanon.
"Iranian and Syrian governments have never put an obstacle in the way of the formation of a unity government in Lebanon and the two sides' agreements have always been welcomed by Iran and Syria," he said.
"Iran and Syria have not interfered in appointing ministers."
Israeli commandos boarded the ship before dawn on Wednesday in the waters near Cyprus.
The ship, the Francop, is operated by the United Feeder Services, a Cyprus-based shipping company that said it picked up the cargo in Damietta, Egypt, according to the Associated Press news agency.
However, the Israeli military said an Iranian document was found on board, showing that the arms shipment originated from Iran.
|The weapons were in ordinary shipping containers, according Israeli officials [AF]
Lieutenant-Colonel Avital Leibovich, an Israeli military spokeswoman, said: "It's a cargo certificate that shows that it was from a port in Iran.
"All the cargo certificates are stamped at the ports of origin, and this one was stamped at an Iranian port."
Rear Admiral Roni Ben-Yehuda, the deputy Israeli navy commander, said "hundreds of tonnes" of weapons were found.
His estimate was much higher than an earlier one of more than 60 tonnes.
The weapons were "a drop in the ocean" of arms being shipped to Hezbollah, Ben-Yehuda said.
Howver, Israel had not provided evidence that the arms were meant for the Lebanese group.
Al Jazeera's Jacky Rowland, reporting from Jerusalem, said: "It's interesting to point out the timing of this announcement.
"The fact that the Israeli army chose to hold the press conference exactly the same time as the UN General Assembly was beginnning its debate on the Goldstone report [on the Israeli war on Gaza].
"At the very least, the timing of this announcement was convenient. If one were cynical one could even suggest that actually the announcement was timed to, if anything, to distract some of the attention of the media in Israel from the Goldstone report."
The Israeli army insists that it was operating under existing international protocols for boarding and inspecting ships when it seized the vessel, our correspondent said.
Quoting officials who addressed a news conference after the seizure, Rowland said the weapons were in ordinary shipping containers hidden among hundreds of other containers on board the vessel.
"They say it was clearly an attempt to disguise the containers as ordinary civilian cargo," our correspondent reported.
Reacting to Israel's allegations, Hezbollah said it "staunchly denies any link to the weapons that the Zionist enemy has seized from the Francop ship.
"At the same time Hezbollah denounces Israel's piracy in international waters," it said.
The ship seizure comes three years after Israel and Hezbollah fought a bitter war that ended with a UN-brokered ceasefire. Occasional clashes continue to occur.
The seizure was bigger than a similar haul in 2002, when Israeli military confiscated a vessel with 50 tonnes of missiles, mortars, rifles and ammunition headed for Palestinian fighters in the Gaza Strip.
Hezbollah, which has widespread support in southern Lebanon, was originally established to fight the Israeli occupation of the region.