Giroud joined the Gunners from Montpellier this summer in a reported £9.6m move, but has failed to score in two Premier League appearances so far.
"It takes time to adapt, and it is especially hard for attacking players, but I am optimistic that both Giroud and Podolski can be a success," Pires is quoted as saying in The Mirror.
"I have seen Giroud playing in France and he has the qualities you need in England. He is strong and he has a good touch. He can be like van Persie in my opinion."
"Podolski is very mobile around the pitch and he is a Germany international with many caps," said the Frenchman. "They will adapt.
"Santi Cazorla is someone I know well. He has adjusted to England very quickly and the fans will love him."
Arsenal, who have drawn both their opening league games, are at Liverpool on Sunday.