Investigators are reviewing video footage of the last moments before two men plunged to their deaths during a skydiving accident as they work to determine what went wrong.
The 60-year-old instructor Adrian Lloyd, and his 29-year-old student, Singaporean national Mario Low Ke Wei, died during a tandem skydiving lesson near Wilton, southwest of Sydney on Saturday afternoon.
It's understood the pair took off from the nearby Sydney Skydivers centre, which was also their intended landing zone, but crashed onto a private property about one kilometre away.
Authorities don't believe any rules were broken during the jump, which has been described as "not especially challenging".
"So far we have not seen any reason to think that there is anything untoward or any regulations broken," a spokesman for the Australian Parachute Federation, Brad Turner said on Monday.
Safety officers from the parachuting regulator are working with police and the skydiving company as they investigate what caused the fatal accident.
"We are a lot closer (to determining)," Mr Turner told the Seven Network.
"At the moment we're trying to get as many witness statements as we can; we're reviewing footage and investigating the equipment over the coming days."
Mr Low's devastated sister, Angeline, says her family is looking for answers.
"Always thought tandem jump is safe. We need a closure to this," she told News Corp Australia.
The young man, who loved deep sea fishing, had only recently moved to Sydney for work in June.
Mr Lloyd had completed nearly 10,000 skydives and had nearly 30 years experience in the sport.
The skydive would not have been especially challenging for the highly experienced instructor, Sydney Skydivers said in a statement on Facebook.
"Our sympathies go out to the families and friends of both men as well as those in our skydiving community," the company said.
"We are doing our best to ensure any support is provided to our staff, skydivers and those involved at the scene itself."
All skydives were cancelled on Sunday out of respect for the two men.