Spectacular artwork emblazoned on to the Opera House at dawn heralded the start of Australia Day in Sydney, before hundreds rallied against the national holiday later in the morning.

Kamilaroi woman Rhonda Sampson’s vivid artwork was projected onto the Opera House sails, as the Australian and Indigenous flags were raised in unison on top of the Harbour Bridge, in a symbol of unity, recognition and inclusion.

“I hope my artwork provides an opportunity for us to reflect on and learn about the connection Gadigal people have always had with the land and waters,” Sampson said.

“This day brings up a lot of feelings and we need to reflect on that.”

Hundreds showed the depth of their feelings at the annual “Invasion Day” rally.

The crowd called for land rights, an end to deaths in custody and the abolition of the national Australia Day holiday as they rallied in Sydney’s Belmore Park on Thursday.

In the 31 years since the Royal Commission into Aboriginal deaths in custody, there have been more than 500 additional deaths.

In a fiery speech, Wiradjuri woman and Greens candidate for the NSW upper house Linda June Coe called for people to reject the federal government’s upcoming referendum on an Indigenous Voice to parliament, labelling it a “fallacy”.

“White Australia, this is the reckoning – 235 years and we ain’t going nowhere,” she told the crowd.

“They tried to wipe us out, still here. They tried to breed us out, still here. They tried to commit genocide on us, still here!

“Brisbane, Melbourne, we are all mobilising against the fallacy that is constitutional recognition. My people, this is the voice.”

The day also marks the 20th anniversary of the WugulOra smoking ceremony at Barangaroo.

The ancient ceremony, attended by dignitaries including Premier Dominic Perrottet and Governor Margaret Beazley, cleanses the way for new beginnings and celebrates the Gadigal people of the Eora nation through music, dance, language, story-telling and ceremony.

There were performances by Aboriginal and Torres Strait Islander dancers and singers, including the Koomurri Aboriginal Dance Troupe and singer Christine Anu.

Yvonne Weldon, deputy chair of the Australia Day Council of NSW, said Australia Day was a time to reflect.

“Every day we walk in our ancestors’ footsteps, and as we gather it’s important to reflect on our past, commemorate and honour those who have gone before us and our history – and celebrate the survival of our people, our culture and our history,” she said.

Amid the controversy, some businesses, including Deloitte, KPMG, CSL and other large companies have allowed employees to work on Australia Day and take a day of leave at another time.

A full suite of traditional official events will include the Sydney Harbour Splash, with swimmers competing in a 2.5km or 5km swim.

With temperatures expected to hit 33C, thousand of people are expected to gather along the harbour foreshore for the Ferrython – one of the most popular and iconic events as well as a fast jet fly past, the tall ships race and regatta.

– AAP