Australian Prime Minister Tony Abbott, having called Japan his country's closest friend in Asia, will seek this week to overcome Chinese unease about his loyalties in a region beset by territorial tensions.

Abbott is visiting Japan, a strategic ally, and China, his country's biggest economic partner, in his first visit to northeast Asia since taking office almost seven months ago. The trip is aimed at giving momentum to free trade deals with both nations, which together account for a third of Australia's annual trade.

With the U.S. looking to its allies to counter a more assertive China, and Japan embroiled in a dispute with its neighbor over contested islets in the East China Sea, the task for Abbott, 56, will be to balance long-standing diplomatic leanings against the need to safeguard economic ties with China.