Irish start-ups raised €545m in the first half of the year - up 25% on the same period of 2019 - however that figure masks some "very worrying trends" according to TechIreland.
The figure for the first six months of 2020 was the highest recorded in four years, according to TechIreland, the independent organisation that promotes Irish start-ups.
However it said it was distorted by three investments; involving Fenergo, Let's Get Checked and ALX Oncology, which account for around 40% of the total figure.
Its latest Startup Funding Review found that the number of companies raising funds was 20% lower year-on-year, while there was a particularly sharp drop in the number of firms fund-raising for the first time.
Early stage firms also appeared to be struggling at the moment, with just three founded in the past year raising a combined €340,000.
In regional terms Dublin saw investment levels increase, however the number of funding rounds fell by more than a quarter.
Cork saw significant growth in activity, with €88m raised by eight firms - compared to €37m raised by five firms a year ago.
However the rest of the country saw funding levels fall slightly, with funding into Northern Ireland halving to €12m.
The second half of the year was "likely to be challenging for companies and investors alike" as a result of Covid-19 according to Niall McEvoy, manager of Enterprise Ireland's High Potential Start-Up programme.
Director general of the Irish Venture Capital Association, Sarah Jane Larkin, also expressed concern about the coming months.
"Experience from the last recession shows that, in addition to a reduced rate of VC funding, other investors tend to step back during times of uncertainty," she said. "That is particularly perilous for vulnerable tech startups."
TechIreland pointed to one positive in its latest report, which was a growth in the number female-led companies gaining investment, and an increase in the amount they raised.
In the first six months of the year 16 female-headed firms raised €60m, compared to 11 firms raising €43m in the same period of 2019.