Finland's Tax Administration said on Friday that it was missing account numbers for 40,000 people who are due to be paid tax refunds in the coming months.
The deadline to supply an account number for refunds due in August is on Monday 27 July, and individuals should use the OmaVero online system to notify authorities of their account numbers.
Tax authorities will never ask for this information by email, the safest way to provide it is via the secure login at the OmaVero service.
If taxpayers do not supply an account number, they will receive a money order for the amount and will have to pay a fee to have it cashed.
The next tax refunds are due to be paid on 4 August.
"But is our money not good enough for you? Some 40,000 tax refund recipients have still not told us their account numbers," said the Tax Administration on Twitter on Friday.
In June the Tax Administration had said that it was missing account details for 90,000 people.
According to Tax Administration figures some 1.9 million people will receive tax refunds in August, with another 700,000 refunds to be sent out in September.
Altogether some 500 million euros is to be paid in August and September.
August is also the time when back taxes are due to be paid, with some 330,000 Finns due to pay their remaining taxes for 2019 on 3 August. The total revenue for the tax man will come to some 105 million euros.