The airport was earlier this month approached by a consortium of infrastructure investors with an offer of $8.25 per stapled security.

“The boards have concluded that the indicative proposal undervalues Sydney Airport and is not in the best interests of security holders,” it said in a statement on Thursday.

It concluded the timing of the offer, coming in the wake of the coronavirus pandemic and ahead of Australia opening its borders at some future point, was “opportunistic”.

“The indicative price is below where Sydney Airport’s security price traded before the pandemic,” it said.

Sydney Airport is Australia’s major gateway to international travel and the country’s busiest domestic hub.

It also owns on-ground retail assets and earns money from car parking and ground transport and other property.

“Sydney Airport is strongly positioned to deliver growth as vaccination rates increase and we move into the post-pandemic recovery period,” it said.

“Sydney Airport will only progress a change in control transaction on terms that deliver and recognise appropriate long term value.”

Sydney Airport securities ended on Wednesday at $7.80 per security, giving it a market value of $21 billion.

The securities traded at a record high of $9.06 on December 6, 2019, before the pandemic took hold in Australia.

They have traded at less than $6 for much of this year and last year, as COVID-19 concerns decimated travel demand.

But the airport could still be a takeover target despite rejecting the bid from the Sydney Aviation Alliance group, which includes Queensland superannuation fund QSuper.

There has been speculation in financial markets that Macquarie Group is considering a tilt at the company, or that the alliance could come back with an increased offer.