HCL Salary Negotiation

Hello Folks,

Can I negotiate the salary again with HCL HR before accepting the offer letter because in HR round they offered me the less package as compared to my experience and also what are the chances of increasing the package up to the expected package. Currently I am not having any counter offer. Is there any chance that HR will take into consideration and will increase the package and regenerate the offer ? What is the best approach for negotiation with HR - through mail or through Phone. Looking forward for replies from HCL guys.