You are not allowed to take out a Dutch basic health insurance if you are in the Netherlands for study purposes only. If you are in the Netherlands for study purposes only, you can take out Private health insurance or European Health Insurance (EHIC).
If you start a (part-time) job or if you start an internship that pays at least the Dutch minimum wage, you are required to take out a Dutch basic health insurance.
Dutch basic health insurance is more expensive than private insurance, costing around €1,500 a year. This might also be more expensive than your current insurance. Keep this in mind if you want to seek employment in the Netherlands in addition to studying. The cost of Dutch basic health insurance may make working less worthwhile for you as you would merely be working to pay your insurance.
If you are required to take out Dutch basic health insurance but fail to do so in time, you risk having to pay a fine of around €425 and a penalty of around 130% of the nominal premium for each month that you are uninsured.
You can contact Zorgverzekeringslijn for any questions about basic Dutch health insurance. Visit zorgverzekeringslijn.nl or (if you are in the Netherlands) call 0800 64 64 644 (week days 09:00-17:00). From abroad, you can call +31 88 900 6960.