I have a Schengen Visa which expires one month before the end of my employment permit (TWV) in Netherlands.
I arrived in Netherlands one month before expiry of the Schengen Visa (expires 23 July 2015), but my work permit is valid for 2 months (expires 21 Aug 2015).
Is it valid for me to stay until end of employment permit or I should stay only based on validity of the Schengen visa only?
The TWV (Tewerkstellingsvergunning) is a work authorization for people who do not need a visa, either because they already have one (regular short-stay visa like yourself, student visa…) or because they don't need one (people who don't need a visa for short stays in the Schengen area based on their citizenship, asylum seekers, Croatian citizens…), yet do not automatically have the right to work (unlike, say, other EU citizens who always have the right to work without needing either visa or a work authorization).
The TWV not a residence permit or long-stay visa, does not replace a visa and does not open any independent right to stay in the Netherlands. In fact, I don't know if that's what you did but what often happens is that an employer requests a TWV to be allowed to hire someone and that person then uses the TWV to apply for the right visa.
If you would have come to the Netherlands to work longer than three months, you would instead get something called a GVVA (Gecombineerde vergunning voor verblijf en arbeid or “combined permit for stay and work”), which is in fact a kind of residence permit and does also give you the right to stay in the country. But since you don't have one and merely have this work authorization, you are not allowed to stay after the end of your Schengen visa without another title (e.g. another visa, a residence permit or an extension of the visa you already have).
I assume your Schengen visa is Work Permit Visa.
I'd say no. But you should check with the embassy. I was in the same situation when I was working in Germany. I had to extend my visa. Generally speaking you are allowed to stay up until your expiry date of your work permit Visa. If anything you have to extend your work permit visa to 21 Aug 2015.
