YANGON, MYANMAR - US Senator Jim Webb is due to arrive in Myanmar on Friday, US and local officials said, planning to become the first senior American official to meet the country's junta chief Than Shwe.

Democrat Webb is flying from Laos where he launched a two-week tour of the region on Thursday, and is expected to land in Myanmar's administrative capital Naypyidaw at around noon (0530 GMT), US embassy spokesman Richard Mei said.

A Myanmar official speaking on condition of anonymity confirmed that Webb, who is close to US President Barack Obama, was due to arrive in the capital on Friday and travel to the commercial hub Yangon on Saturday.

Neither Mei nor the Myanmar official were able to confirm a statement from Webb's office in which he said he was due to meet military strongman Than Shwe.

News of Webb's visit comes after Tuesday's convictions of opposition leader Aung San Suu Kyi and an American man who swam to her lakeside house. Than Shwe extended her house arrest by another 18 months.

Webb - a hard-nosed Vietnam veteran who chairs the Senate Foreign Relations subcommittee on East Asia and Pacific affairs - would be the first senior US official to meet Than Shwe.

The White House Thursday welcomed Webb's visit, which is also the first by a member of Congress in more than a decade, saying he would convey "strong" US views of good governance to the junta's leaders.