Manager Arsene Wenger failed to sign Leicester City forward Jamie Vardy, and Manuello suggested that any incoming striker would be a replacement for the injured Danny Welbeck, not for Giroud.
"Everything I've read on Giroud is not true. I personally have only said that if Arsenal want to sell, then we will see," Manuello told London's Evening Standard.
"I do not know where (the Napoli story) came from. We never talked to Naples and there are no other persons appointed over me that can do this - we need to clarify this.
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"You always need two strikers and Welbeck is out for (a total of) nine months, unfortunately. But if you play in a great team, it is natural that we could face strong competition."
Arsenal, who finished second in the Premier League last season, begin their new campaign on Aug. 14, when they host Liverpool.
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by Kevin Liffey)
