Iran is ready to let Japanese-related vessels pass through the Strait of Hormuz, a vital artery for global oil supplies, Kyodo news reports, citing Iranian Foreign Minister Abbas Araqchi.
Tehran has started talks with Tokyo about possibly opening the strait, Araqchi told the Japanese news agency in a phone interview on Friday.
Japan's foreign and trade ministries and the Prime Minister's Office did not pick up calls from Reuters on Saturday seeking comment on the report.
Japan gets around 90 per cent of its oil shipments via the strait, which Tehran has largely closed during the US-Israeli war on Iran.
A spike in global oil prices sparked by the war, which enters its fourth week on Saturday, has prompted Japan and other countries to release oil from their reserves.
US President Donald Trump met Japanese Prime Minister Sanae Takaichi on Thursday, urging her to "step up" as he presses allies - so far unsuccessfully - to send warships to help open the strait.
Takaichi told reporters after the Washington summit that she had briefed Trump on what support Japan could and could not provide in the strait under its laws.
Japan's actions are limited under its postwar pacifist constitution, but 2015 security legislation allows Japan to use force overseas if an attack, including on a close security partner, threatens Japan's survival and no other means are available to address it.