Subject to the provisions of rule 23, if an application is presented by any party to the proceeding for the summoning of witnesses, the Claims Tribunal shall, on payment of the expenses involved, if any, issue summons for the appearance of such witness unless it considers that their appearance is not necessary for a just decision of the case:
Provided that if, in the opinion of the Claims Tribunals, the party is financially poor, it may not insist on the payment of the expenses involved and the same shall be borne by the Government:
Provided further that in case where the party succeeds in whole or in part, the expenses so incurred by the Government shall be directed to be paid to the Government by the opposite party.