Thousands of Ukrainian citizens queue outside Warsaw's National Stadium as they wait to register for their Polish ID numbers.
But the sheer number of refugees applying means many are being asked to come again the next day, and the next day again.
Poland's electronic ID numbers, called PESEL, allow for quick identification by employment, tax and social care offices, by the health care and education systems.
Those with PESEL numbers will be able to take jobs, send children to schools and take them to the doctor.
They will be entitled to 500 zlotys ($117) a month of benefits per child under the age of 18, and will receive one-time benefit of 300 zlotys ($70.)
Registration for Ukrainian refugees began on Wednesday, and queues have been forming every day at administrative points since.
Those who joined the huge line outside the National Stadium at 8 a.m. on Saturday were told they came too late, and need to come Sunday.
According to the Polish government, there are 100 work stations inside the arena to tackle the volume of people signing up.
Some 123,000 refugees have been given Polish ID numbers across Poland since Wednesday, with more than 1,000 issued a day in Warsaw.