Erdogan wants to change the Turkish constitution to turn the ceremonial role of president into that of a chief executive, a Turkish version of the system in the United States, France or Russia.
Asked on his return from a visit to Saudi Arabia late on Friday whether an executive presidential system was possible while maintaining the unitary structure of the state, he said: "There are already examples in the world. You can see it when you look at Hitler's Germany.
"There are later examples in various other countries," he told reporters, according to a recording broadcast by the Dogan news agency, Reuters reported.
The ruling AK Party, founded by Erdogan, has put a new constitution at the heart of its agenda after winning back a majority in a November parliamentary election.
It agreed with the main opposition CHP on Wednesday to revive efforts to forge a new constitution.
Opposition parties agree on the need to change the constitution, drawn up after a 1980 coup and still bearing the stamp of its military authors, but do not back the presidential system envisaged by Erdogan, fearing it will consolidate too much power in the hands of an authoritarian leader.