Eddie Jones would "definitely be interested" in coaching Japan but has yet to receive an offer, Japanese media quoted the former England and Australia boss as saying.
The 63-year-old Australian has been strongly linked with a return to the team he led from 2012 to 2015, one week after he quit as Wallabies head coach following a disastrous spell in charge.
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Speaking to reporters in Yokohama on Tuesday, Jones said he had not held any formal discussions with the Japan Rugby Football Union but would welcome an approach.
"I've had no offer, let's be clear," said Jones, according to Kyodo News and other prominent local media.
"If they came to me and said, are you interested in coaching them, I'd definitely be interested."
Jones's wife is Japanese and lives in the country. His mother is Japanese-American.
Jones is reportedly the front-runner on a JRFU list of candidates that also includes South African Frans Ludeke, who coached Kubota Spears to last season's Japanese club title.
Ludeke is set to be interviewed this month for the job, which previous coach Jamie Joseph left after Japan's first-round World Cup exit.
Australian media reported that Jones had held an online interview with the JRFU while coaching the Wallabies at the World Cup, something which he has strenuously denied.
Jones told reporters in Yokohama that Japanese rugby had "always been my passion".
"Japan can't stay where they are because if they stay where they are, they'll actually start to slide," he said.
"So they've got to make a big push now."
Jones led Japan to a historic win over South Africa at the 2015 World Cup in England, in a match that became known as the "Miracle of Brighton".
His success with Japan helped land him the job as coach of England, who he took to the 2019 World Cup final and eventual defeat by South Africa.
Jones was fired by England last December having won just five of 13 Tests in 2022.
He was hired by Australia in January but quit last week after two wins from nine Tests, including a worst-ever World Cup performance where the Wallabies failed to make it out of the pool phase.
Jones said he was denied the chance to reform Australian rugby and he said Japan also needs to make major changes.
"You're going to have to be courageous and you're going to have to do things differently," he said.
"You can't just go along and do what you're doing now. So that's the reason I would be interested."