Araqchi told reporters in New Delhi on Friday that all vessels can pass through the Strait of Hormuz except those "at war" with Iran, if they co-ordinate with the Iranian navy.
But the situation around the waterway, vital to global energy and commodities markets, was "very complicated," he added, during a visit to attend a BRICS foreign ministers' meeting in India.
In a post on X, Araqchi said he told India's Foreign Minister Subrahmanyam Jaishankar that "Iran will always carry out historical duty as protector of security in Hormuz".
Iran largely shut the strait, which normally handles about one-fifth of the world's seaborne oil and gas supply, to most shipping after the US and Israel began their war on Iran in February.
The US and Iran announced a ceasefire last month but have been struggling to thrash out a lasting peace pact.
Talks mediated by Pakistan have been suspended since Iran and the US each rejected the other's latest proposals last week.
Araqchi said "contradictory messages" had raised Iranian doubts about the real intentions of the United States, adding that the Pakistani mediation process had not failed but was in "difficulty".
"The messages we receive from the American side vary from day to day ... Sometimes we even receive several different messages in a single day," Araqchi said.
"Every day they name different targets. We really hope that reason and wisdom will return to the White House," he said.
The United States and Israel have cut short two previous rounds of talks with Iran in the past 13 months by launching campaigns of air strikes on Iran.
Iran is trying to keep the latest ceasefire to give diplomacy a chance but is also prepared to go back to fighting, Araqchi said.
The issues holding up negotiations between the two sides include Iran's nuclear ambitions and its control of the Strait of Hormuz.
Hours before he spoke, US President Donald Trump said his patience with Iran was running out and said he had agreed in talks with Chinese President Xi Jinping that Iran must reopen the strait.
Asked if Iran was open to mediation by China, Araqchi said Iran appreciated the efforts of any country that had the ability to help.
"We have very good relations with China," he said.
"We are strategic partners, and we know that the Chinese have good intentions. So, anything they can do to help diplomacy would be welcomed."
Araqchi added: "We hope that, with the advancement of negotiations, we will reach a good conclusion so that the Strait of Hormuz can be completely secured and we can expedite the normalisation of traffic through the strait".
with DPA
