World Rugby chief executive Brett Gosper admitted the COVID-19 pandemic has been "devastating from a revenue point of view".
The governing body has been supporting rugby unions since the global health crisis caused the suspension of sport in March.
This included a relief fund of $100 million (£77 million/€85 million) announced in April.
Rugby matches have since resumed, with the men's Six Nations completed this week, but most have taken place without spectators.
Gosper revealed this has put unions "under huge pressure", but seemed hopeful the crisis would be eased by next year.
"It's been devastating from a revenue point of view," he said, as reported by Daily Mail.
"The more reliant you are on ticketing and hospitality revenue, the more devastating it is.
"Hopefully we'll be getting some good broadcast revenues, but the rest of the picture is pretty weak.
"We're operating a little bit like a central bank, advancing monies to unions to see them through this period from a cash flow point of view.
"It's the highest revenue unions that are most in trouble and they're under huge pressure.
"The majority of the money goes to the top 10 unions because they generate a lot of the money for other unions - it's important that we help them be cash-viable for as long as possible.
"Hopefully we can see this through if things get back to normality - whatever that is - halfway through next year."
Gosper suggested there had been some positives from the pandemic, however, claiming unions had been more willing to "get together and collaborate" on different competition models.
World Rugby held a Professional Game Forum in June, allowing national unions, international and professional club competitions and players to exchange views about calendar reform.
This helped ensure the Six Nations was completed and is allowing the Rugby Championship 2020, which features Argentina, Australia, New Zealand and South Africa, to take place in full in Australia over seven weeks.
"If the pandemic has served something, it's been constructive in focusing people's minds to see if we're looking at the right model," Gosper said.
"It's unlikely you'd get calendar change, if that was recommended, before 2024.
"And if there was window change, it's unlikely that would happen before 2024.
"There are some alternatives on the table.
"A number of competition models being run through separate or combined windows.
"We're in the kitchen still and can't predict where this will end up.
"But the willingness to get together and collaborate has been refreshing."