In the first four months of the year the number of persons caught crossing the land border illegally in the Koper area rose by 325% year-on-year, from 162 to 526.
These were mainly citizens of Syria, Algeria, Kosovo, Afghanistan, Pakistan and Tunisia.
In the first eight days of May the Koper police recorded another 105 illegal migrants crossing the border, most of whom asked for asylum.
Migrants and refugees mostly cross the border in the Ilirska Bistrica area, near the border crossings of Jelšane and Starod and near the Šapjane-Ilirska Bistrica railway.
In the area covered by the Piran police, the most critical areas are near the Sečovlje and Dragonja border crossings, while in Koper they cross over in Podgorje, Tuniši and Hrvoji.
The Koper police and investigators processed 22 cases of illegal border crossing this year.
In some cases, the criminal act was committed by individuals, but it was mostly organised crime groups who helped refugees cross borders illegally from Turkey through Serbia and Bosnia-Herzegovina to Croatia and on to Slovenia.
Eight suspects have been remanded in custody, while another 23 persons were apprehended and charged last year.
In the first three months of this year, the Koper police department returned 52 persons to the Croatian authorities, three to the Italian and one to the Austrian. In 2017, 74 persons were returned to the countries they came to Slovenia from.
In this period, 145 persons said they would request asylum in Slovenia, while 197 persons were denied entrance, which compares to 154 in the same period last year, the Koper police said.
Last Friday, a 52-year-old Bosnian citizen was caught transporting four Kosovo citizens across the border in his car in Tuniši. The driver was remanded in custody, while the Kosovars, aged between 17 and 22, requested asylum.
The number of illegal border crossings has also been rising in the south-eastern region of Bela Krajina, where 462 illegal migrants have been registered so far this year, but none in the same period last year.
In all, the Novo Mesto Police Department recorded 509 illegal migrants so far this year, which compares to 62 in the same period last year.
Data from the General Police Administration show the total number of illegal border crossings reaching 955 by 22 April this year, which is a 246% increase on the same period last year.
The number of migrants filing for asylum increased in the first three months of the year from 192 in 2017 to 524 this year.
Only last week, 83 migrants were caught crossing the border illegally near the Vinica and Metlika border crossings in Bela Krajina.
They were citizens of Pakistan, Algeria, Morocco, Iraq, Tunisia and Libya. All of them asked for asylum and were transported to the asylum centre.
This week at least another 14 citizens of Pakistan and Algeria were apprehended in the region. They all asked for asylum.