PM offers condolences at AIDS conference

Prime Minister Tony Abbott has expressed his deep condolences to the colleagues and friends of the six HIV researchers and lobbyists who died on Malaysia Airlines flight 17 while travelling to Melbourne for an international conference.

"Australians share with you the pain you feel as this conference commences," Mr Abbott said via a video message at the opening ceremony of the 20th International AIDS Conference on Sunday.

"The terrible circumstances surrounding the loss of MH17 are a challenge to us all.

"298 men, women and children are no longer with us and their passing defies our sense of justice.

"We honour all who have died."

Mr Abbott also highlighted the death of AIDS humanitarian Jonathan Mann, who died in a plane crash on the way to an AIDS conference in 1998.

"Another world leader in the fight against AIDS, Dr Jonathan Mann, who also died in a plane crash, said when speaking of his work - and your work - "we will prevail together - for we will refuse to be split".

"We will prevail together".

He urged everyone "to rededicate ourselves to the work of those who were lost".

Mr Abbott was unable to travel to Melbourne due to commitments in Canberra as part of the federal government's response to the tragedy, including a meeting of National Security Committee of Cabinet.

Deputy Prime Minister Warren Truss attended the opening ceremony in place of Mr Abbott.