How long would it take for me to apply for a working permit?

Usually, it takes around four weeks to getting the working visa for HK.

Thank you for your answer. I was told by someone from the embassy here in the Netherlands that - as a Dutch citizen - I can apply for my papers in Hong Kong. Does that indicate I can start work upon arrival, while my papers are being processed? Or that I would have to wait until they are processed? In the latter case, I would prefer to apply from here.

You can apply an ordinary type in HK, but since you will apply for a work visa, you cannot do that in HK. You cannot start to work first in HK and then hand in your papers for that permit. It is illegal. You need to apply for it first and then go to work in HK.

Thank you, and the application to get a working visa for Hong Kong takes four weeks?

Yes, you are right. It also takes that long time.