Under the plans Altmann would be tasked with a review of financial fairness for consumers, including looking at charge caps for pension products.
Mr Cameron said the appointment would make sure "we complete this revolution where we are giving people more power to save to access their pension, to pass their pension on to their children because we want to create a real saving culture in our country for everybody, not for the rich at the top but everybody who saves and has a pension".
The Conservatives are also examining other ideas for improving banking services and competition within the sector, such as allowing customers to take their account number with them to a new bank.
Altmann said: "It's vital that ordinary savers have protection from rip off charges and from unusual practices.
"The pensions industry has relied on people not understanding what the terms are in terms of savings and it is now time that ordinary people are given fair treatment, clear and fair charges.
"What I'm really excited about is the opportunity to become a minister and to protect the public... in terms of looking after their savings, being treated fairly by the big financial companies and also rolling out financial education to younger age groups not just focusing on the people who are at the end of their saving lives."