The holdings would raise about pounds 4bn at current share prices. A Treasury spokesman said the sale would take place in 1994-95 subject to market conditions but no decision had been taken on the size, structure or exact timing.
Kleinwort Benson already advises PowerGen, but the generator said it had agreed to seek a separate broker to act for it during the sale. National Power's brokers are Smith New Court and Cazenove.
Last month the regulator, Offer, decided not to refer the generators to the Monopolies and Mergers Commission, clearing the way for the Government to dispose of its shares. But they are still under close scrutiny by Offer concerning prices in the wholesale electricity market.
A spokesman for National Power said it welcomed the government appointments and looked forward to a speedy conclusion of the sale.