Qatar Airways is to press on with plans to build a stake of up to 4.75 per cent in American Airlines in the near future, despite the "categorical" opposition of the US company's management, said a report.

The move by Qatar Airways would expand its investments to North America at a time when Qatar is embroiled in the region's worst diplomatic crisis in years and is locked in an airspace rights row with three other Gulf states, reported Reuters.

The state-owned carrier had notified American Airlines last month that it was interested in buying up to 10 per cent of its shares but would not exceed 4.75 percent without the approval of American's board, stated the report, citing its top official.

"We will be able to start buying shares in the open market soon, depending of course on what is the share value," Qatar Airways CEO Akbar Al Baker told reporters in Dublin, where he was launching a new Qatar Airways route.

However, American said in a regulatory filing dated June 22 that company rules prohibit anyone "from acquiring 4.75 percent or more" of the company's shares in issue without prior board approval.

Shares in American were up 1.88 per cent at $53.03 on Friday, valuing the company at over $25 billion, it added.