It's not going to happen. The police tried to run this scheme, and the ISPs almost fell for it. Then the minister of justice noticed what was going on, investigated it, and concluded that it was against the law (!).
Bit of a shame though. The agreement between ISPs and the police was much better then any future law will be .. which unfortunately is still just as likely as anywhere else in the world.
It had very good checks and balances built in. For example, the agreement was in the form of a contract, and it would become invalid the moment any non-child-porn site showed up on the list.
Oh well. All in all I'm happy it didn't go through. But I'm wondering what they will come up with next.