Iranian foreign ministry spokeswoman Marzieh Afkham condemned the Saudi-led attack on Yemen as "genocide".
"Such actions by the Saudi-led coalition have been genocide and go counter to the international conventions," Xinhua quoted Afkham as saying on Sunday.
In their attack on Yemen of more than 40 days, they have used "unconventional weapons intended to increase the number of the casualties", she said.
She urged the active role of the United Nations to stop the raids on Yemen and immediately dispatch aid to the vulnerable people.
Iran's decision to send relief to war-stricken Yemen has been coordinated with related international bodies, she said, adding that it is expected the aid will be received by the Yemeni people on Sunday evening.
A ship carrying 2,500 tonnes of humanitarian aid, including food and medicine, is due to arrive at the Yemeni port of Hodeidah on the Red Sea.
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On board the ship, there will be 15 medical staff, 13 media representatives, seven anti-war activists from the US, France, and Germany and the crew members.
The ship, coded Rescue Ship, will leave the Iranian southern port city of Bandar Abbas to Hodeida through the Sea of Oman, Indian Ocean, Gulf of Aden and the Red Sea.
The International Committee of the Red Cross and Red Crescent Authority of Saudi Arabia, Oman and Djibouti is co-ordinating with Iran.
Iran has warned the Saudi-led coalition against intercepting the ship.
"Regional security along with Iran's is intertwined with Yemen's security," Iran's Deputy Foreign Minister for Arab and African Affairs Hussein Amir-Abdollahian had said last week.
Last month, fighter jets of the Saudi-led coalition intercepted an Iranian plane over the Yemeni air-space and destroyed the runway of Sanaa airport to prevent it from landing.
Iran said the plane was carrying aid to Yemen.
Earlier reports said that the US warships had also intercepted the Iranian ships near Yemen's waters last month.
Saudi Arabia has long been accusing Iran of arming and financing Houthi fighters, an accusation strongly rejected by Tehran.
Airstrikes by a Saudi-led coalition on Houthi rebels in Yemen have been going on since late March.
More than 1,000 people have been killed and 3,000 injured in the air-strikes and in the battle between the Shiite Houthi group and tribal militia loyal to President Abd-Rabbu Mansour Hadi.
Earlier in the day, Yemen's Shiite Houthi group and the army welcomed a Saudi proposal for a five-day cease-fire to allow aid to be delivered to the country.
"We welcome the five-day humanitarian truce announced by the Saudi foreign minister that will start on Tuesday," Houthi spokesman Hussein al-Ezzy said.
In a press conference with US Secretary of State John Kerry, Saudi Foreign Minister Adel al-Jubeir said the cease-fire would begin on Tuesday night and the implementation was contingent on cooperation by the Houthis.
Saudi-led coalition forces, however, continued its air-strikes overnight on Yemen's capital Sanaa and the northern Saada province, the stronghold of the Houthi group.
On Saturday, Iranian President Hassan Rouhani said the Saudis are making a "very big strategic mistake" by bombing Yemen.