Notarised poa for sale of immovable property

The Indian Registration Act does not list a Power of Attorney as a compulsorily registerable document. However, it states that if a power of attorney holder presents a document for registration as an agent of another, then it should have been authenticated. This means that the executants should have got the power of attorney authenticated (there is hardly any difference between authentication and registration for practical purposes) in the sub registrar’s office, which has jurisdiction over where he resides

The courts have held that if a sale deed is signed by the power of attorney holder on behalf of the owner and presented for registration, the power of attorney need not be authenticated (registered) If the sale deed has been signed by the owner and presented for registration by the power of attorney holder, then the power of attorney should be registered.

i think you have got the answer if it is registered or not no problem but authentication is necessary check out 

In context of above reply, kindly elaborate how does a sub-registrar authenticate the GPA unless it is registered! I mean to say what is the method of authentication other than registration!

autentication means you have produce before the sub registrar paying a nominal fees with that they will keep a copy with them and another copy will be with you which is registered with a document number 

and also enquire with your local sub registrar office you have to submit an form also