Some 4,600 people have paid a total of €312 million so far in the Revenue's investigation into life insurance products.
Investigators are following up about 3,500 cases where people sent in a notice of intention to the authorities but then did not make any further communication.
The investigation is targeting people who put lump sums into insurance products without paying tax on the money.
What is happening today is the latest step in an investigation which could take up to three or four years. This probe goes back to 1980 when insurance companies began selling single premium policies.
Some invested lump sums without paying tax and those people were asked to disclose to the Revenue how much they owed by May. They had to pay the tax owed by last Friday.
But the authorities have given some leeway to people who have had to sell assets to raise the money.
Revenue said that the success of the special investigations approach is now 'well established' and recoveries now exceed €2 billion.
