Up to 500 Australians and their close relatives are due to be boarded on to two charter flights out of Beirut on Saturday, amid increased government efforts to expatriate citizens after Israel’s ground incursion into Lebanon’s south.

The first flight was expected to fly out of the Lebanese capital and land in Cyprus at about 11.30am local time (6.30pm AEST). From there, two Qantas flights can take passengers to Sydney on Tuesday and Wednesday.

Guardian Australia understands that seats were still available for the flights as of Saturday afternoon (Australian time)

Speaking to reporters on Saturday, the federal infrastructure minister, Catherine King, said the government’s message to Australians in Lebanon was “do not wait”, adding it could not be guaranteed that everyone would be evacuated.

An estimated 15,000 Australians are in Lebanon. As of Saturday afternoon, there were 4,901 Australians who had registered their interest to evacuate the country – more than double the 2,300 registered on Friday.

Of those, 3,088 were registered as wanting to depart, and 1,813 were registered for information only. More than 700 people had departed or self-closed their registration.

“Do not wait to get the perfect flight home to that connects you everywhere,” King said. “If you are offered a flight, then you need to go. You need to leave now and take that first available opportunity.

“The situation on the ground is very serious and we cannot guarantee that we can get everybody out.”

A Canadian assisted-departure flight left on Thursday evening, carrying 41 Australians on board, the foreign minister, Penny Wong, has previously confirmed.

She said while the government had indicated there would be further flights planned in the coming days, they would be subject to demand and Beirut’s airport remaining operational.

The government was working with other airlines to confirm additional flights.

“Our message to Australians in Lebanon remains – now is the time to leave,” Wong said on Friday afternoon.

The flights were free of charge for eligible citizens, permanent residents and their immediate family members with a right of entry to Australia, Wong said. Vulnerable passengers and those ready to depart immediately were being prioritised for access.

Passengers were expected to arrive at Beirut airport from 6.30am local time for the first flight, and 11.30am for the second. The second flight was expected to land at 4.45pm local time (11.45pm AEST).

Accommodation in Cyprus had been arranged for those eligible for assisted departure, Guardian Australia understands, with planning for the onward journey to Australia under way.

Qantas confirmed the two non-stop flights to Sydney would be operated using a Qantas Boeing 787 and could carry up to 440 Australians.

“The airline is working to obtain the necessary approvals,” the airline said.

“Qantas has called for pilots and cabin crew to nominate their interest in operating the flights. This is expected to be oversubscribed as it was with the special assistance flights from Tel Aviv in October 2023, when 900 cabin crew expressed their interest for 70 positions.”

Qantas said the assisted departure flights would affect “some customers” booked to travel internationally, who were being contacted directly with alternative travel arrangements.

“We’re working to minimise the impact as much as possible and appreciate their understanding,” the company said.