Qantas is Australia’s largest airline and has been in discussions with a range of individuals and companies, including other airlines, discussing possible acquisitions, joint ventures and partnerships.
Analysts quoted by the Associated Press said there was speculation Macquarie was preparing a cash offer of A$5.50 a share, valuing the airline at almost US$8.47bn.
However, several hurdles would have to be overcome for the takeover to be successful.
Regulations limit foreign ownership of the airline to 49 per cent, and there is a limit of 25 per cent equity for any single partner.
Earlier this year, Qantas reported a net profit of US$370m for the year to June - a 30 per cent drop on the previous year which was blamed on soaring fuel costs.
The Qantas Airways Group has a fleet of 219 aircraft and has firm orders for 20 Airbus A380 superjumbos, the world's largest passenger aircraft.