“We will never forget the men, women and children on board that fateful flight,” said Governor-General Peter Cosgrove to around 1700 mourners packed into St Patrick’s Cathedral for a national memorial service.

“To those of our fellow Australians who remain in the depths of their loss, we cannot ease the burden you bear, but today, and always, we will honour your loved ones - and we will be with you to help you carry them.”

He addressed the crowd of dignitaries, children, families of the victims and even strangers, who listened to the 90-minute service on Thursday to remember the 38 Australian citizens and residents who died when the Malaysia Airlines passenger jet was shot down over Ukraine last month. Eighteen of those who died were from Victoria.

The service was punctuated by moving speeches from political and religious leaders, and haunting renditions of well-known songs, including Katie Noonan singing “I am Australian” to close the sombre service.

Families of the victims filled nearly a quarter of the church. It took 15 minutes for all of them to place flowers at a yellow wattle wreath as screens placed around the church displayed photos of their loved ones. Many of them cried and rubbed each other’s backs while the Australian Boys Choir echoed throughout the cathedral.

Queenslander Paul Guard, who lost his parents in the July 17 plane crash, said the service had brought him some comfort as he was able to pause, reflect and, after the service, meet other families.

“It was a good event for us. It’s part of the healing process,” he said.

“I wish there was more that everyone could do. I wish the Australian government or the UN or world leaders were able to somehow bring an end to the violence because it would be just horrific for my parents if they knew what was going on.”

Malaysia Airlines Flight 17 came down near the Ukraine-Russia border while en route from Amsterdam to Kuala Lumpur, killing all 298 people on board.

Intelligence agencies and government officials have concluded the aircraft was shot down, likely by Russian-backed rebels fighting for control over eastern Ukraine.

The area is still a heavily-contested conflict zone, leading to great difficulty in securing the site and recovering the bodies of victims.

An estimated 228 coffins have left Ukraine for the Netherlands as a Dutch-led humanitarian effort stalled again on Thursday due to heavy fighting in the area.

Prime Minister Tony Abbott said Australia will never abandon those who have died, no matter how difficult it could be.

“There will be a time to judge the guilty, but today we honour the dead and we grieve with the living,” he said in his speech at the service.

“We can not bring them back, but we will bring them home as far as we humanly can.”

Opposition Leader Bill Shorten told mourners the plane crash had united the country like a “single garment of grief". But he could never understand the pain that the loved ones of MH17 victims are experiencing, he said.

“Today is not about why or how, it is about who we have lost and who we will miss,” he said.

“Some will call it closure, some it will call it acceptance, some will call it letting go. Whatever it is, it will take a while.”

The service drew in many people who had no connection to the downed airliner and the victims.

Heike Jindra said she was had felt personally impacted by the incident despite the lack of a connection.

“It’s devastating,” she said. “It just hurts to know that one family lost all three children, and the father. It just hurts.”

Mary Fennesy attended the service with her mother. While she didn't know anyone on board the doomed flight, she said she had often flown on MH17 and felt compelled to pay her respects.

“It was a beautiful service, just so moving and so dignified,” she said while walking out of the church.

“Everything about it was lovely. And it did make me proud to be Australian.”