N'Zogbia, who won his first cap for France earlier this month, was left out of last weekend's shock season-opening loss to Blackpool.
It has been claimed the 24-year-old, who has been linked with Birmingham and Sunderland, has fallen out with Martinez and is agitating for a move but the Spaniard insists that is not the case.
Martinez said: "Charles is a Wigan Athletic player and that is the top and bottom.
"He has been working really hard and been training well. We will have to get used to speculation and rumours and we need to take it as a compliment when other clubs want to take our players.
"Unfortunately this is the instability the window brings to a club like ours.
"He will be working hard to play in every single game and that is what every player should be doing.
"Since he came back from international duty he has been training hard, working really well and fighting hard for his place with everyone else.
"It is rumour and speculation and something you are not going to stop."
Martinez says N'Zogbia could return on Saturday as Wigan face a daunting visit from Premier League champions Chelsea.
N'Zogbia's form since his £6million move to the DW Stadium from Newcastle last year has made him an attractive proposition to other clubs.
Martinez accepts players will always be linked with bigger sides but insists they will not leave without adequate replacements lined up.
He said: "If we lose a player, I will make sure we are a stronger football club the day after because the structure we have put in place will be able to bring more players in."
Martinez has already bolstered his squad in the summer window by bringing in James McArthur, Antolin Alcaraz, Ronnie Stam, Mauro Boselli and Ali Al Habsi.
He added: "We lost nine players in the summer and brought five in so, if you do the maths, we are light in numbers.
"We are starting to build a strong squad but we still need a few extra bodies for the demands of the Premier League."
Newly-appointed captain Gary Caldwell is making encouraging progress in his recovery from double hip surgery.
The 28-year-old Scotland international has had two operations since the end of last season but could be fit sooner than expected.
Martinez said: "We expected Gary probably to be fit at the end of November but maybe we will see him a lot earlier than that.
"That is how well he has been working and how well he is responding to treatment.
"He has got a great influence here. He is a special human being and I think he is going to have a great year at Wigan Athletic."