Settlements worth almost €10m were made with the Revenue Commissioners between April and June this year.
It has published the latest tax defaulters list.
A total of 43 settlements were made - which occurs when voluntary disclosure is not used, and the default arises because of "careless or deliberate behaviour."
Twenty-one of these cases were for amounts exceeding €100,000, of which six were over €500,000.
Some 19 are cases still outstanding, in which the settlement was not fully paid as of June 30th.
Revenue says this outstanding amount stands at more than €6m.
But it adds: "Revenue vigorously pursues collection/enforcement of unpaid settlements.
"In some cases, collection/recovery of the full unpaid amount will not be possible (for example, company liquidation)".
A vehicle test centre operator in Wexford was told to pay nearly €706,000 for non-declaration of income tax and under-declaration of VAT.
While a Cavan-based wholesaler is to pay over €852,000 for the same offence.
And a car dealer in Galway is to pay just under €800,000 for under-declaration of VAT.
There were also nine such cases where a court determined the penalty - with the total amount reaching just over €591,000.
And there were 176 where a court imposed a fine, totaling over €550,000.
In one instance, a Cork-based subcontractor faced seven charges for failure to lodge income tax returns.
He had to pay a fine of €28,000.
While a Wexford farmer was fined €17,500 for her failure to lodge VAT returns.
A window installer in Wexford paid a penalty of nearly €125,000 for under-declaration of income tax and non-declaration of VAT.
While a Monaghan-based property developer was order to pay €125,043 for non-declaration of Capital Gains Tax.
The full lists can be seen here