Australia has never won more than four gold medals in a single day of Olympic competition but that record could be smashed on day one in Paris

Australia is poised to match its most successful day in Olympic history, with swimmers expected to lead a golden charge as competition gets underway at the Paris Games.

Chalmers and Ingeborg Løyning announced their engagement in June this year, putting an end to the 'love triangle' rumours once and for all.

In Tokyo three years ago, the Australian team won four gold medals in a single Olympic day for the first time, shining in the pool, on the open water and at the skate park.

Swimmer Emma McKeon started the gold rush when she won the 50m freestyle and then combined with Kaylee McKeown, Chelsea Hodges and Cate Campbell to take out the 4x100m medley relay.

Logan Martin dominated the men's BMX freestyle before sailor Matt Wearne ensured a new Olympic green and gold benchmark.

But that could be equalled, or even eclipsed, on the first day of competition in France on Saturday with Australian athletes legitimate gold-medal chances in four of the 14 events decided in eight sports.

Another swimmer, Ariarne Titmus, is tipped to star.

The 23-year-old will open her medal campaign in what's been dubbed the 'race of the century', with defending 400m freestyle Olympic champion Titmus taking on American legend Katie Ledecky and Canadian starlet Summer McIntosh.

The trio squared off at last year's world championships, where Titmus won in world record time.

The quartet of Mollie O'Callaghan, Emma McKeon, Shayna Jack and Meg Harris will start unbackable favourites to win gold in the 4x100m freestyle relay after shattering the world record last year.

The Australian men's 4x100m freestyle relay, anchored by Kyle Chalmers, doesn't have the same star power as the women but a podium finish is still expected, though the United States start the event as overwhelming favourites.

Australia also has two genuine medal chances in the men's 400m freestyle in 2023 world champion Sam Short and Queenslander Elijah Winnington, who won their Olympic trial.

Back at the 2000 Olympics, Ian Thorpe got the Games off to a blazing start when he streeted his rivals to win the 400m freestyle in world-record time before anchoring the men's 4x100m freestyle relay team, also in a new world mark.

A silver and bronze medal at the velodrome then capped a remarkable opening day for Australia on home soil.

Away from the swimming in Paris, the women's 3m synchronised diving will be decided with Rio bronze medallists Anabelle Smith and Maddison Keeney among the favourites after pocketing silver at this year's world championships in Doha.

After placing fourth in Tokyo, cycling star Grace Brown is expected to be in the medal hunt in Saturday's 32.4km road time trial.

The 32-year-old has won silver at the last two world championships but faces stiff competition from Dutch and American rivals.

Australia's men's rugby sevens team are also right in medal contention after an unbeaten start in Paris.

With their program getting underway before the opening ceremony, the men have booked a semi-final showdown with defending Olympic champions Fiji.

Cult skateboarding figure Shane O'Neill underperformed in Rio but the veteran could surprise in the men's street event on Saturday, while Australia has gold medal hopes in the women's equivalent and park discipline later in the Games.