Paralympic sport got under way in Tokyo on Wednesday, after a high-energy and poignant opening ceremony, with the first golds up for grabs in cycling, wheelchair fencing and swimming.

The national stadium hosted the colourful opener on Tuesday night, themed around the story of a one-winged plane trying to fly, in tribute to the tenacity of thousands of para athletes competing at this year's Games.

"Many doubted this day would happen, many thought it impossible, but thanks to the efforts of many, the most transformative sports event on Earth is about to begin," International Paralympic Committee chief Andrew Parson said.

Despite the triumphant atmosphere after a year-long pandemic postponement, with beaming athletes dancing their way into the stadium, the spectre of coronavirus will hang over proceedings.

The 68,000-capacity stadium in central Tokyo was almost empty, as venues will be throughout the Paralympics, because of virus rules barring almost all spectators.

Still, for athletes who have spent years preparing, the competition will be all that matters.

A total of 24 gold medals are being contested on the first day of sports in cycling track, wheelchair fencing and swimming.

Competition is also getting started in some of the team sports including wheelchair rugby, the often brutal clash dubbed "murderball".

Stars appearing Wednesday include Brazilian swimmer Daniel Dias, who is competing at his last Paralympics and has the chance to become the most decorated male Paralympic swimmer of all time.

He already holds a haul of 14 gold, seven silver and three bronze medals, and could overtake the current record holder if he can snag another three golds.

Australian wheelchair rugby player Ryley Batt will also be hitting the court in a faceoff with Denmark as the Aussies bid to become the first team ever to win three straight gold medals.

Records smashed

Athletes were already shattering records in heats.

Britain's Sarah Storey began her bid to make Paralympic history in style Wednesday by smashing her own world record in heats of track cycling's C5 3,000 metres individual pursuit.

Storey has the chance to add three golds to her haul and eclipse swimmer Mike Kenny, who won 16 golds between 1976 and 1988, as Britain's greatest Paralympian.

The virus situation continues to weigh on the event though, with organisers on Wednesday reporting 16 new positive virus cases linked to the Paralympics, including two athletes in the Paralympic Village, whose identities have not been disclosed.

The new cases bring the number of infections linked to the Paralympics to 176, most of them Japan-based staff or contractors.

The Games are beginning with Japan tackling a record surge in infections, with 13 regions including the capital under a virus state of emergency.

The measure, which largely limits bars and restaurants from selling alcohol and shortens their opening hours, is to be expanded to a further eight regions as the government attempts to check the spread of the highly contagious Delta variant.

Japan has recorded around 15,500 deaths from the virus, and around 40 percent of the population is now fully vaccinated.

Olympic and Paralympic organisers have insisted there is no evidence of infection spreading from Games participants to the Japanese public.

All those involved in the Games have to abide by virus countermeasures including regular testing and some limits on movement.

But some experts have warned that holding the Games has undermined the government's messaging on the virus, encouraging people to go out and mingle.