Union leaders have called for new rules to allow post offices to issue repeat prescriptions as part of a radical plan to expand services.
MPs have been urged to switch a vast range of services to post office branches in rural areas as well as city centres, to generate new sources of income to secure the network's future.
Andy Furey, national officer of the Communication Workers Union, said post offices were "trusted and traditional outlets" for Government services and are suitable to issue prescriptions.
But the chairman of the business and enterprise select committee, Peter Luff (Conservative), said that while the ideas for expansion were "interesting" they could be "problematic".
Mr Furey has also called for post offices to be given the authority to process court fines to free up services elsewhere at the same time as supporting the future of the organisation.
He said that crown offices, the larger branches, should be extended and upgraded to make them "bigger and brighter" and big enough to offer a large variety of services for local people.
The union submitted a list of service suggestions which it believes could be dealt with at post offices, including help with filling in Government forms, visas for foreign travel, tax self-assessment as well as repeat prescriptions.