The International Paralympic Committee is this week to hold urgent crisis talks with the Brazilian government over an $8m (£6m) budget shortfall, amid fears that up to 40 countries may not be able to compete.

It has emerged that Rio 2016 organisers have yet to hand over up to $8m in travel grants to the competing countries. The grants are considered crucial for many smaller national paralympic committees to be able to reach Brazil.

Insiders fear that last-minute crises in Rio, such as the rush to finish the athletes’ village and issues with the diving pool, have led organisers to use money earmarked for the Paralympic Games for the Olympics instead.

The travel grants are already more than a fortnight late and there are serious fears that many countries in Asia and Africa will not be able to compete in the Games, scheduled to begin on 7 September, if they do not receive the money soon.

Even for better-funded competing countries such as Paralympics GB, which will take a team of 259 plus officials and support staff to Rio, it will leave a six-figure hole in their budget.

IPC president Sir Philip Craven will meet with senior government officials in Brasilia this week in an attempt to resolve the crisis, while the organisation’s chief executive, Xavier Gonzalez, is due to meet Rio’s mayor, Eduardo Paes.

The situation is further complicated by a Brazilian court judgment that placed a freeze on any further public money being channelled to the Rio organising committee until its books can be scrutinised. The organising committee is challenging the ruling.

The IPC has long been concerned that the focus on getting Rio ready for the Olympics against the backdrop of public spending cuts and a deep recession would have a knock-on effect on the Paralympics.

It is already cooperating with organisers over making cuts to certain areas of the Paralympics budget, including reducing the number of media centres and cutting back on transport. There are even concerns that if the funding crisis is not addressed, some sports may have to be cut from the programme.

Rio 2016’s spokesman, Mário Andrada, admitted that organisers were looking at making cuts to the Paralympics, but insisted funding shortfalls would be covered.

“We had to make cuts in the Olympic Games to balance the budget and we need to produce similar cuts to make sure the Paralympics also balances, but there is no intention to compromise the Paralympic experience,” he insisted.

“We have discussed this with IPC and are making arrangements. When it comes to the management of cash in events like this we have enough friends and partners to fix all the problems.”

Within the Paralympic world, there is concern that the Rio Games will represent a step backwards following the success and sold-out stadiums of London. With annual revenues of $12m that just about cover its outgoings, the IPC does not have any money to plug gaps in the budget. The IOC, on the other hand, sits on a surplus of almost $1bn.

The funding crisis is just the latest threat to the Rio Paralympics, amid concern over ticket sales and logistics.

Last week, the IPC confirmed that it would ban Russia from the Paralympic Games after evidence emerged of widespread state-sponsored doping over a period of four years involving many Olympic and Paralympic sports.

The decision, made in stark contrast to the IOC’s stance that allowed 278 Russian athletes to compete, was praised by anti-doping bodies, but widely criticised in Russia.