The International Paralympic Committee (IPC) expects to fill at least 85 per cent of the 267 competition spots available after their suspension of the Russian Paralympic Committee (RPC) was upheld.
The RPC was banned from all IPC competitions on August 7 following revelations of state-sponsored doping in two independent reports commission by the World Anti-Doping Agency (WADA).
An appeal against the ban was lodged with the Court of Arbitration for Sport (CAS) but the RPC's claim was dismissed on Tuesday, ending the chance for any Russian to compete at the Paralympic Games in Rio.
The IPC will reallocate the 267 slots that had been secured by Russian athletes and anticipates at least 85 per cent of them being filled.
"We're fairly confident we'll be able to fill the majority. We're working hard and I think we're confident that between 85 and 90 per cent of the slots will be redistributed to other nations," IPC media and communications director Craig Spence told Omnisport.
"There's a lot of work going on behind the scenes at the moment but we're optimistic that we'll be able to redistribute 85 per cent of the slots.
"Some nations will benefit from this. It doesn't mean 267 slots will go to one nation, they'll probably be split across a number of nations who can take them up at such late notice.
"Hopefully we'll get them all redistributed by the end of the week."
Planning for the Games has been hit by major cuts from the Rio 2016 Organising Committee, with the late payment of National Paralympic Committee (NPC) grants leading to concerns 10 countries may be unable to finance sending their teams.
However, Spence confirmed the IPC has received a guarantee the funds will be transferred this week and believes there will be a full complement of eligible nations in Brazil.
"The Rio 2016 [Organising Committee] has confirmed to us that they will pay the travel grants this week," he continued.
"We've been in touch with those  countries this week and the majority have already secured either government funding or funding from elsewhere to act as a stop gap for them to go to the Games.
"So we're confident that all 165 countries will be on the start line at Rio 2016 from the seventh of September."
Rio 2016 Organising Committee spokesperson Mario Andrada said on August 17 only 12 per cent of tickets for the Paralympic Games had been sold.
Spence revealed sales surged following success for Brazil on the final Olympic weekend, bringing cause for optimism.
"Now that the Olympics are over they [the Rio 2016 Organising Committee] are pressing full steam ahead promoting Paralympic tickets," he said.
"We've been significantly helped by Brazil winning gold in the football and volleyball at the weekend, and getting the message out to the Brazilian people that if they want to see more success then the Paralympic Games is for them.
"We saw yesterday that we sold 100,000 tickets in just 12 hours, and if you consider that we'd only sold 300,000 in the last 12 months to sell 100,000 in 12 hours is a real step forward in the right directions for us.
"We're optimistic we will have good strong crowds in Rio for the performances the athletes are going to put on."