During her address to a 500-strong crowd at the commemorative service marking 20 years since the Port Arthur massacre, Professor Warner said it was one of three layers of tragedy experienced in the area.

Professor Warner described an attempt to remove Aboriginal people from the Tasman Peninsula in the 1830s and Port Arthur’s subsequent history as a penal settlement as previous tragedies to befall the site.

“The events of  April 28, 1996, have added another layer to a place that has ensured so much,” she said.

Professor Warner was part of a number of politicians, survivors and community leaders who paid tribute to victims by laying wreaths by a memorial cross.

She said the massacre would be forever part of Tasmania’s history but did not define its people.

“By acknowledging the massacre today we are saying to the world that this event happened, and we won’t forget it or the suffering that it caused. Rather it will become part of the narrative of this place, another layer in its history,” Professor Warner said.

The service featured a scripture reading from Premier Will Hodgman, music performed by a school choir and opera singer Amelia Farrugia, who was at Port Arthur on the day of the massacre, poetry, and a minute of silence.

Prime Minister Malcolm Turnbull said April 28 was set to be “another calm day amid the sandstone ruins”, before Bryant killed 35 people and wounded 23 others.

"Despite the years, despite the healing, the sense of loss weighs heavily. We will never be the same,” he said.

Mr Turnbull said Australians stood alongside those who had lost loved ones and witnessed the massacre.

“The evil that was committed here must never be allowed to overshadow our memory of each of those individual lives, of their humanity, of their goodness, of how they were loved and cherished before they were taken from us,” he said.