An Adelaide couple who were booked on a Malaysia Airlines flight which crashed in Ukraine are lucky to be alive after changing their flights at the last minute.

Simone La Posta says she and her husband were booked to fly from Amsterdam to Kuala Lumpur on Malaysia Airlines flight MH17 but instead decided to leave a day earlier.

“We originally had our itinerary to be on that flight but then we changed it thinking we’d be too jetlagged for work on Monday,” she told ABC radio.

“It’s a bit surreal to think that one day later and I wouldn’t be here talking with you right now.”

The couple almost didn’t make it onto the earlier flight because it was overbooked.

“We were on standby and we only found out literally a minute before the boarding closed that we were actually going to be leaving that day,” Ms La Posta said.

The government has confirmed 27 Australians were on board Flight MH17 which was carrying 298 people, including 15 crew.

It’s believed there are no survivors.