The tragedy of Malaysia Airlines (MAS) Flight MH17 has exposed an "uncomfortable truth", that there are no clear standards to determine whether a flight path is safe.

Prime Minister Datuk Seri Najib Razak pointed out that the International Civil Aviation Organisation (ICAO) - the United Nations global aviation body - issued advice on areas to avoid, but did not declare flight paths unsafe.

Najib said as airlines revealed their vastly different approaches to conflict zones, passengers were left wondering who ensured the safety of the skies.

In an article published in the Financial Times, he said in the weeks after MH17, it became clear that carriers differed vastly over conflict zones.

Illustrating his point, Najib added: "Germany’s Lufthansa, which flew over Ukraine, avoided northern Iraq and Israel. Australia's Qantas flew over Iraq but avoided Ukraine and Israel. British Airways flew over Israel but avoided Ukraine and Iraq."

He said this happened because airlines did not share their risk assessments, and this must change.

In the piece titled, 'Our skies will not be safe until nations share their knowledge', the prime minister said after MH17, the international community must choose collective security over national interest.

They should commit to sharing flight risk information - among airlines, aviation bodies and nations.

"In so doing, we can honour those who lost their lives by making our skies safer for all," said Najib.

Flight MH17 was en route to Kuala Lumpur from Amsterdam when it crashed in eastern Ukraine on July 17, killing all 298 people aboard, including 43 Malaysians. The aircraft was believed to have been shot down.

Najib stressed that responsibility for the lives lost lay with those who brought down MH17.

"We'll pursue every avenue to bring them to justice," he vowed.