Erdogan said he wondered how German officials could look Turkey's leaders in the face after Thursday's vote in the Bundestag, which prompted Ankara to withdraw its ambassador and warn of further consequences, AFP reported.
But he said it was "too early" to talk of economic measures against Germany.
And he said the dispute with Berlin should not be a factor in Turkey's wider relationship with the European Union, acknowledging it would also do Turkey no good "to act with hate".
"The decision taken by the German parliament has no value whatsoever," Erdogan said in comments to Turkish newspapers including the Hurriyet daily while on a trip to Africa.
"Our position on 1915 is well known... and this kind of decision is not going to change what we think about our history. But they also overlook the fact they face the risk of losing a friend like Turkey."
Armenians say some 1.5 million of their people were killed in a genocidal campaign by Ottoman forces to wipe them from Anatolia, but Turkey has long refused to recognize the killings as genocide.
He expressed disappointment over conduct of Chancellor Angela Merkel, who stayed away from the debate, saying he wished she had taken part "and cast her vote".
"Now I wonder how, after such a decision, German officials will look at me personally and our Prime Minister (Binali Yildirim) in the face," Erdogan said.