Scott Morrison has come under fire for mounting an unusual argument about why January 26 is a tough date for some people.
The prime minister said Australia Day - also known as Invasion Day - was an important date to reflect on how far the country had come.
He spoke about the experience of those aboard the First Fleet, who raised the Union Jack for the first time on January 26, 1788 after arriving the previous week.
"On Australia Day, it's all about acknowledging how far we've come," Mr Morrison told reporters on Thursday.
"You know, when those 12 ships turned up in Sydney, it wasn't a particularly flash day for the people on those vessels either."
The prime minister is a descendant of William Roberts, who came to Australia as a convict aboard the Scarborough in the First Fleet.
Critics have accused Mr Morrison of drawing a false equivalence between those aboard the First Fleet and the experience of Australia's Indigenous people.
Aboriginal and Torres Strait Islander people were living on the continent for more than 60,000 years before the British arrived.
Indigenous people have since endured widespread massacres, oppression and dispossession.
For many Indigenous and non-Indigenous people, January 26 is a day of sorrow and mourning.
Another of Mr Morrison's critics - Labor MP Graham Perrett - also pointed out there were actually only 11 ships in the First Fleet.
"Luckily our prime minister doesn't have an electorate connected with this event," Mr Perrett quipped.
The prime minister represents the seat of Cook, named in honour of Captain James Cook, a navigator in the Royal Navy who is credited as the first European to discover the east coast of Australia in 1770.
Australian Associated Press