An indigenous smoking ceremony honouring the past and the future has launched a wide range of Australia Day celebrations on and around Sydney Harbour.

Aboriginal celebrants on Sunday morning lit a fire at the Sydney Opera House before the flame, along with offerings from around the world, was carried aboard a boat.

The vessel met up with bark canoes under the Sydney Harbour Bridge and a traditional smoking ceremony was carried out.

Tens of thousands of Sydneysiders and visitors have been flowing into the city for the celebration, billed as the biggest in Sydney since the Bicentenary, with more than 14 hours of entertainment planned.

Rain showers did not deter the people flowing in, some waving Australian flags or wearing green and yellow face paint.

Events on and around the harbour include an RAAF flypast and display, a 21-gun salute by the army, a swimming race around Farm Cove, a race of decorated harbour ferries, a tug and yacht ballet, a tinnie muster, tall ships and a parade of colourfully decked out vessels of all shapes and sizes.

The army’s Red Beret parachutists were also to put on a display and the 178th Australia Day regatta featuring up to 90 vessels, including classic yachts, was to get underway from 1.30pm (AEDT).

The Australia Day Sydney Harbour Concert series got underway from 1pm starring some of Australia’s most popular young musicians.

Singers Mahalia Barnes and Prinnie Stevens will entertain with the sounds of motown in Darling Harbour from 6pm and at 8.45pm fireworks will mark the finale of the festivities on the harbour.

A Sydney Symphony Orchestra concert is also billed at the Domain from 8pm.

A 100-year-old Iraqi-born grandmother and a two-year-old Indian boy were among nearly 3,600 people from 113 countries to become citizens across NSW on Sunday.

Meanwhile, face painting, an animal farm and a 3pm concert with The Wiggles will be rolled out at Hyde Park through the day to keep the kids entertained.

Further west in Sydney’s Olympic Park, about 6,000 Sydneysiders are expected to head to Bicentennial Park for fireworks, sheep shearing, whip cracking and sheep dog trial shows.

At Newcastle a national maritime festival will be held from 8am to 5pm.

Across the state, police say they will be targeting drink driving and are urging people to slow down after almost 800 speed infringement notices were issued on day one of the long weekend campaign.