The passage of two Iranian naval ships through the Suez Canal has been put back to Wednesday, a canal official said on Sunday as Israel expressed its grave concern about the Mediterranean-bound vessels.

"The shipping agent handling the two Iranian warships has told the canal administration to push back their passage by two days," the official told AFP on condition of anonymity.

He did not elaborate on the reasons for the delay, but confirmed that the new day of passage through the waterway that links the Mediterranean Sea to the Red Sea would be Wednesday.

Reportedly bound for Syria on a journey that would necessarily involve passing Israel, the patrol frigate Alvand and support ship Kharg would be the first Iranian warships through Suez since the 1979 Islamic revolution.

Officials at the Egyptian-run canal had previously said privately that they expected the two ships to pass on Monday, just days after the US aircraft carrier Enterprise steamed through Suez in the opposite direction.

In the wake of president Hosni Mubarak's ouster on February 11, Egypt gave its green light on Friday for the Iranian warships to transit the canal into the Mediterranean.

Egypt's official MENA news agency has reported that the request for the ships to transit the Suez Canal said they were not carrying weapons or nuclear and chemical materials.

The 1,500-tonne Alvand is normally armed with torpedoes and anti-ship missiles, while the larger 33,000-tonne Kharg has a crew of 250 and facilities for up to three helicopters, Iran's official Fars news agency has said.

Both ships were built in Britain during the 1970s for Iran, which ordered them before the Islamic revolution.

Earlier on Sunday, after a weekly meeting of his cabinet, Israeli Prime Minister Benjamin Netanyahu denounced the ships' arrival in the region as an Iranian power play.

"Today we are witnessing the instability of the region in which we live and in which Iran is trying to profit by extending its influence by dispatching two warships to cross the Suez Canal," he said.

"Israel views with gravity this Iranian initiative and other developments that reinforce what we have said in past years about the Israel's security needs," he added, according to a statement from his office.

Earlier this week, Israel Foreign Minister Avigdor Lieberman called the move a "provocation."

But an Iranian diplomat said: "This will be a routine visit, within international law, in line with the cooperation between Iran and Syria, who have strategic ties."

"The ships will spend a few days in Syrian ports for training purposes," having already visited several countries including Oman and Saudi Arabia," the diplomat added.