how many days to apply for the government issued permit from PRC?

Can you specify the permit? If you have Z, X1 or Q1 type, you should change it to a temporary resident permit within 30 days after you come to PRC.

thank you william. i need a z type one. they said it will take a long time to acquire a permit or authorized invitation coming from the government of china.

Yes, your employer has to get the duly authorized invitation letter from the foreign affairs office. It usually takes 5 working days. However, it might take longer time if they have to report to the provincial level foreign affairs offices or make investigations on you.

I thought it would take a month or longer.. :) thank you so much!