President Xi Jinping hailed China's "solidarity" with Iran on Tuesday as he hosted the Islamic republic's President Ebrahim Raisi at the start of a three-day trip.

In the first state visit by an Iranian president to China in more than 20 years, Raisi has brought a large trade and finance delegation to Beijing and was earlier greeted by Xi on a red carpet.

"In the face of the current complex changes in the world, times, and history, China and Iran have supported each other (and) worked together in solidarity and cooperation," Xi said, according to state broadcaster CCTV.

As reported by the broadcaster, he added that China "supports Iran in safeguarding national sovereignty, independence, territorial integrity and national dignity... and in resisting unilateralism and hegemonism."

Beijing also "opposes external forces interfering in Iran's internal affairs and undermining Iran's security and stability", and will continue to "promote the early and proper resolution of the Iranian nuclear issue", the state leader said.

"No matter how the international and regional situation changes, China will unswervingly develop friendly cooperation with Iran", Xi added.

According to CCTV, the two sides signed a number of bilateral cooperation documents in the fields of agriculture, trade, tourism, environmental protection, health, disaster relief, culture and sport.

Raisi and Xi met for the first time last September at a Shanghai Cooperation Organisation summit in Uzbekistan, where the Iranian president called for expanded ties.

According to the Iranian state news agency IRNA, Raisi will take part in meetings with Chinese businessmen and Iranians living in the country.

China is Iran's largest trading partner, IRNA said, citing 10-month statistics compiled by Iranian customs authorities. Tehran's exports to Beijing stood at US$12.6 billion, while it imported US$12.7 billion worth of goods from China.

Raisi is being accompanied by the country's foreign minister and the ministers for the economy, roads and transportation, and oil. Also attending is the minister for industry, mining and trade, as well as the minister for agriculture, according to Iranian state television.

His delegation also includes Ali Bagheri, Iran's deputy foreign minister for political affairs and its chief nuclear negotiator.

Foreign ministry spokesman Wang Wenbin said Raisi would meet with Premier Li Keqiang and top Chinese legislator Li Zhanshu. (Agencies)