The Taoiseach has said the HSE is doing everything it can to make more PCR tests available.
There has been a shortage of available tests, with people reporting having to queue online at midnight when more become available.
The HSE has been carrying out around 200,000 PCR tests a week amid the current wave of cases, with the health service also using private testing capacity in order to meet demand.
In the Dáil today, opposition TDs raised concerns about the situation - with Labour TD Duncan Smith suggesting there's a "scramble" for private capacity to be used.
He said an "unbelievable" amount of tests are being carried out, but it's still "just not good enough".
He noted: "If you logged in right now at lunchtime... you would not be able to get a test. You'd have to stay up late, until 12 o'clock at night, refreshing screens to try to get a cancellation test."
Taoiseach Micheál Martin insisted the number of tests being carried out is massive.
He said: "Having a capacity of 207,000 [a week] is not scrambling around - the amount of private sector additionally is low compared to the core capacity provided by the HSE.
"I think credit where credit is due to the HSE... they're looking at every possible way to increase it further."
He suggested there needs to be a "positive message" sent out to the public about what has been achieved in ramping up testing capacity.
Meanwhile, the Government is also under renewed pressure to offer antigen tests to people free of charge.
A number of opposition parties have called for the move after a delay was confirmed on the introduction subsidised antigen testing.
Health Minister Stephen Donnelly was supposed to bring a memo outlining how the cost of antigen tests would be subsidised to €2-3 per test.
However, the plans are being pushed back as talks continue with retailers.
Sinn Féin's Health Spokesman David Cullinane today said the Government needs to go further and make the tests "freely available".