The IRFU says it's facing an 'unprecedented cashflow crisis' and will lose at least €62 million this year.
The organisation says the very existence of professional rugby could be under 'significant threat' in 2021.
Representatives of the GAA, IRFU, FAI and Sport Ireland will all appear before the Oireachtas COVID-19 committee today.
The IRFU will say its key issue is the absence of spectators and the situation is 'catastrophic' financially.
Its net losses are forecast at €30 million this year, but a further €32 million won't be taken in as a result of money owed from ten-year ticket sales.
The union says the IRFU and the provinces will continue to 'burn' €5 million a month, mainly on wages, and that's not sustainable.
It will say the professional game across the island of Ireland could be under 'significant threat' in 2021.
The GAA will also say its financial situation is also 'stark'.
It faces a €50 million hole in its finances this year, and further losses of at least €20 million expected in 2021.
The FAI will say it has gone from one crisis to another, and the association won't survive financially without fans attending international and League of Ireland games.
It will say League of Ireland clubs may not be viable in the future.