Mexico's record goalscorer described suggestions that he would seek a move back to his first club Chivas Guadalajara in January as "completely false".
Hernandez was responding to a Mexican newspaper report that said he was intent on a move following the appointment of Moyes, who sidelined him at one of his previous clubs Manchester United.
"I'm 100 percent committed to improve the situation we are in at West Ham," he told West Ham's website (www.whufc.com). "As I've always said, I'm a Chivas supporter at heart but I have absolutely never requested to leave West Ham."
Hernandez started his career at Chivas, scoring 29 goals in 80 appearances after making his debut as an 18-year-old in 2006.
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One of Moyes's first tasks will be to ensure there is no fallout from the pair's time at Old Trafford when the Mexican went from two titles and 50 goals under Alex Ferguson to just six starts and four goals under his successor.
Moyes's appointment as Slaven Bilic's successor at West Ham has prompted an unexpected resumption in their working relationship.
In a season of struggle in which West Ham are 18th, Hernandez is top scorer with four league goals.
Moyes this week straight-batted questions about his relationship with the striker whom he described as a "brilliant finisher".
"He won't be getting any special treatment," the 54-year-old said. "If he is scoring goals and working hard, he will be in. It will be the same for the rest of the team."
Hernandez, who joined from Bayer Leverkusen for 16 million pounds in July, will not play against Watford after damaging his hamstring in Mexico's 3-3 draw with Belgium last Friday.
The injury will also put him out of subsequent games against Leicester City and Everton, three winnable fixtures which could set the tone for Moyes's time in charge.
That should mean Moyes starts with Andy Carroll up front even though the striker has yet to score this season.
(Reporting by Neil Robinson; Editing by Toby Davis)
