Iran says Australia's standing in the Middle East has been damaged by the decision to join the United States in patrolling the Strait of Hormuz.

Key points: An Australian warship and a surveillance plane will be sent to protect shipping in the Strait of Hormuz

An Australian warship and a surveillance plane will be sent to protect shipping in the Strait of Hormuz Iran has been blamed for attacks on six tankers in or near the strait, though it denies any role

Iran has been blamed for attacks on six tankers in or near the strait, though it denies any role Iran said Australia's military move is unnecessary

Kamal Dehghani Firouzabadi, the deputy chair of Iran's Foreign Relations Committee, said Australia was taking a big risk by moving military forces to the region.

"I don't think there'll be material damage to Australia. The damage will be to the reputation and prestige of Australia," he said.

"Those who take part in this coalition are responsible for the damage caused by this coalition."

Mr Dehghani spoke to the ABC inside the Iranian Parliament in Tehran and was responding to Prime Minister Scott Morrison's announcement that an Australian warship and surveillance plane would be sent to protect shipping in the Strait of Hormuz.

"It was very surprising for me to hear that Australia joined the coalition, because the United States is making repeated mistakes, including pulling out of the nuclear agreement," he said.

"This was a multilateral agreement reached by the whole world."

Mr Dehghani says Australia is taking a big risk. ( ABC News )

Iran has been blamed for attacks on six tankers in or near the Strait. It denies any role in the attacks, and decries as propaganda US drone footage that purported to show an Iranian patrol boat crew removing an unexploded limpet mine from a tanker.

Mr Dehghani said Australia's move to the strait was unnecessary. He said Iran already protected oil tankers in the region.

"We still haven't figured out who attacked the ships," Mr Dehghani said.

"But whoever was behind this tension is benefiting from all this. It might be the United States, it might be Israel, or it might be the backward nations like Saudi Arabia, UAE or the terrorist organisations that get their money from them.

"Donald Trump had already stated the US is trying to milk the cow of the Arabian states. They are doing this with Islamophobia. I'm very surprised they are milking the cow of Australia with this strategy."

Parliament sits in Iran, where tensions are brewing over shipping in the Strait of Hormuz. ( ABC News )

In Tehran, most people have not heard of Australia's looming involvement.

It did not come up in the weekly politics wrap by the imam at Tehran's biggest mosque, who told worshippers that Iran sought peace and tranquillity.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 46 seconds 1 m 46 s Prime Minister Scott Morrison says Australia will join efforts to keep the Strait of Hormuz open for shipping

Outside the mosque, Tehran residents expressed defiance, and pride.

"It's the same as the war in Iraq," said one white-bearded veteran of that eight-year war.

"All the countries are against us. It doesn't matter if it's the United States, Australia or the United Kingdom.

"We will stand together and fight them. I fought in that war. I will grab a gun and fight again."

Another worshipper said it showed "that our flag is raised even higher".

"It shows how important we are, and with resistance we will be victorious," she said.

Another resident added: "These sort of moves ... they also make us express our hatred more to Trump and his allies."