For sale of land POA executed in favour of mother by sons has to be on Rs 500 stamp paper and duly registered 

notarised POA would not suffice 

No property transaction can be done through un-registered poa. The poa has to be registered at the place where the property is situated.

1. if the poa from sons to mother contains a power to sell clause, then full stamp duty will be payable on it in respect of the shares of the sons in the property

2. the sale deed can be signed by the parties and the sons can then give only a presentation poa to the mother so that she can appear before the sub-registrar and comply with the registration formalities on behalf of her sons

3. the poa by mother to sons has to be signed before the sub-registrar who has jurisdiction over the place where the mother is presently residing and such poa has to be authenticated by the sub-registrar and not by the notary 

4. the aforesaid is provided in s.33 of the registration act 

5. as regards the stamp paper, it is better to purchase a 500 rs stamp paper [the exact duty has to be ascertained as per the prevalent rule in Karnataka]

So state so in your query itself

I simply wasted my time answering 

Whether its Karnataka or Maharashtra, the registration act is a central act and applies to entire India!!

The POA are being executed in Mumbai as the 2 sons are staying in Mumbai 

2) in Maharashtra POA has to be on Rs 500 stamp paper 

3) further for sale of property registration of POA is mandatory 

1. Registration of POA is a must.

2. The two sons can get the POA registered in Bombay itself for the property located in Karnataka. There's no need to procure stamp paper from Karnataka.

Thanks.

Under the provisions of Indian Evidence Act, a power of attorney executed before and authenticated by a Notary Public carries a presumption that it was properly executed.

Section 85 of the Indian Evidence Act reads:

“85. Presumption as to powers-of-attorney.—The Court shall presume that every document purporting to be a power-of-attorney, and to have been executed before, and authenticated by, a Notary Public, or any Court, Judge, Magistrate, Indian Consul or Vice-Consul, or representative of the Central Government, was so executed and authenticated.”

• in certain states in case the power-of-attorney relates to transfer of immovable property possession whereof has been or is handed over to the attorney holder[10] or where Irrevocable power of attorney relating to the transfer of immovable property is made, that the deed of power of attorney is required to be registered.
• The registration of all other power of attorneys is optional. Yet a registered document carries with it a presumption that it was validly executed. Consequently, it is for the party questioning the genuineness of the transaction to show that transaction was invalid.
•  

Section 33 of Registration Act provides:

“(1) For the purposes of section 32, the following powers-of-attorney shall alone be recognized, namely:-

(a) if the principal at the time of executing the power-of-attorney resides in any part of 18[India] in which this Act is for the time being in force, a power-of-attorney executed before and authenticated by the Registrar or Sub-Registrar within whose district or sub-district the principal resides.

• Therefore, to preempt any possible attack that power of attorney was not duly executed, it can always be registered.

The law is common and applicable through out India.

Since the transaction involves immovable property the registrar may insist on the authenticity i.e., a registered power of attorney deed invoking section 33 of the Registration act, you may have to rush to get the deed registered.

Hence to be doubly sure of the situation, you may enquire about it with local registrar office where you intend to register the deed pertaining to the transaction involving the transfer of  immovable property . 

Dear sir,

Please note that for a POA to be functional and legally valid, it is important that you first get it registered in Mumbai.  The law stated that the POA is to be executed and registered before the Registrar within whose district you reside. This clearly implies that as you live in Mumbai, the POA needs to be registered there. 

Concerning the transfer of property, it will most likely take place in the state of Karnataka. The registration of the sale deed will happen in the Registrar residing in Mangalore and your mother can act on behalf of al owners based on the POA. Thank you.

Firstly, if the property is in the name of mother and her two sons who along with the mother are co-owners of the property then a transfer by way of a POA is only valid if the necessary stamp duty charges are paid. Mere getting the document notarised and selling the property will not give a clear title of the property to the buyer.  Transfer of property by POA is not legally valid as it does not pave way for a clear title.