On Tuesday police apprehended 17 foreigners trying to enter the country by crossing the border Kolpa river in the Bela Krajina region, SE, and six trying to cross near Ilirska Bistrica further west.
They included citizens of Pakistan, Afghanistan, Albania, Turkey, Bangladesh, Iran, Algeria and Myanmar.
Those apprehended on the Kolpa are still being processed, whereas the six arrested near Ilirska Bistrica will be returned to Croatia, the police said.
On Friday, police at the Obrežje border crossing found two citizens of Iraq and three Iranians hidden in a lorry with Bosnian licence plates. The foreigners were returned to Croatia.
By Tuesday, Slovenian police recorded more than 3,200 illegal border crossings, an almost 260% increase compared to the same period last year.
The most popular route into Slovenia is to cross the Kolpa, which is typically shallow but has dangerous stretches of treacherous water.
Nine migrants died in the Kolpa so far and two more remain missing after a boat capsized last Friday, according to media reports.
