KSA job visa, consultancy asking for my original certificates to be submitted for visa stamping?

Hi, I am in India, I have got a job offer in Riyadh, need to join in October'08. They have requested me to co-ordinate with a consultancy in India. Consultancy is asking me to submit all my original marks cards, degree certificates and pport for visa processing. I am hesitant, uncomfortable in submitting the same as I am unaware of process. Request, if anyone have any idea about this process please let me know.