Qantas Airways Limited (ASX:QAN) has been put on notice by the Transport Workers Union (TWU).
The industry union has called on Australian Securities and Investment Commission to conduct an investigation on whether the airline has breached the corporations law.
The TWU have accused Qantas of taking too long to inform the market of its profit downgrade in June.
Rumours that Qantas and its subsidiary Jetstar have been pursuing deals and alliances with other airlines has surrounded Australia's flagship airline recently.
In the first half of the 2012 financial year Qantas reported a net profit of $42 million.