The International Paralympic Committee anticipates the Rio Games will be a sell out after passing 1.5million ticket sales.
The Rio 2016 organising committee admitted as the Olympics came to a close last month that only 12 per cent of the 2.5m Paralympic tickets had been sold.
But the IPC on Monday announced a huge upsurge in sales ahead of Wednesday's opening ceremony.
"The Rio 2016 Paralympic Games achieved an important milestone on Sunday (September 5) as it reached 1.5 million tickets sold," the IPC said.
"Several finals are now fully sold out. The Paralympic athletes can be prepared to display their amazing will and skills in fully booked venues.
"While there are still around 1 million tickets available the rhythm of sales suggests that all the 2.5 million tickets will be sold."
Brazil has high expectations for the Paralympics - including a top five place in the medal table.
Friday's athletics action could engage more Brazilians, with Alan Oliveira likely in the T44 100 metres final.
The race for amputee sprinters is arguably the blue riband event of the Games. Britain's Jonnie Peacock is defending champion and Jarryd Wallace of the United States is world record holder, but Oliveira is among the favourites.
