I don't think any country could stop illegal immigration completely but it's ironic that they were able to stop or minimize the legal migration while the illegal continues. They will probably have to grant those who entered illegally like what the US is does especially when a democrat is sitting as the President.
Legal immigrants you just can fetch them as they are legal and the services know where they live.
Illegals make it harder and some might even get violent, It's not that the police likes violence towards them. Who does really.