Investment activity in the Republic could reduce by up to 50% depending on how long the Covid-19 pandemic lasts, according to a survey carried out by the Irish Venture Capital Association (IVCA).
The survey was carried out among IVCA members to gauge the anticipated impact of the virus on future investment strategy.
Members include SOSV, which has over $700m (£560m) worth of assets under management, and Delta Partners, which has €250m (£218m) under management.
According to Sarah-Jane Larkin, director general of the IVCA, respondents indicated that investment activity could reduce by 20% under the current lockdown measures until May, but may worsen if the rules continue into September.
She said: "People would have targeted a certain amount of capital to deploy, and the estimates in the likely reduction are narrowing from around 20%, so we can say with some certainty there will be a 20% hit this year.
"But, depending on the period of isolation, it could go to as much as 50%."
The IVCA's latest figures show €820m was invested into Irish SMEs last year.
Using this sum, a 20% reduction in investment would result in a €164m (£143m) hit in funding, while a slowing of 50% would result in a slashing of €410m (£358m).
Ms Larkin explained that the period may impact on fund valuations and could result in "a very destructive time" for funds and the industry.
"There is a concern that likely valuation hits may wipe out a firm's track record, making raising future finance difficult," she said.
She added that some investors, such as angel investors and family offices, may "disappear for a while".
Ms Larkin called on the Irish Government to do more to support early-stage companies and those scaling up. Without additional support, she said there was a "strong chance we will see the loss of a generation of future Irish unicorns". A unicorn is a privately held start-up valued at over $1bn.
She recognises that the Irish state has put huge supports in place, but feels more is needed.
"Much of the effort so far is based on supporting companies that are operating successfully, as opposed to those getting off the ground," she said.