Barkley has emerged as one of the hottest properties in the Premier League following a string of hugely impressive performances this season.
The midfielder, who turned 20 earlier this month, has broken into Roy Hodgson's England squad and enhanced his growing reputation with a sublime free-kick that secured victory for Everton at Swansea on Sunday.
Unsurprisingly, Barkley's form has fuelled speculation of a potential move to one of Europe's biggest clubs.
Yet Martinez is adamant Everton, who sit just two points behind Premier League leaders Arsenal, will be holding on to their young star, claiming not even a bid to match the reported £85m Real Madrid paid Tottenham for Gareth Bale would force a sale.
The Spaniard said: "Ross is in a moment of his career where first, he knows that he needs to carry on developing and this is the perfect place to do that.
"Second, he is a mad Evertonian and enjoying every single second. And third, we are in the middle of a season where we would never, ever consider disrupting what we have got in our squad now.
"It is not the right time for the player or the club to consider anything. Even if we got a Gareth Bale-size valuation we would never even consider it in January."
Martinez is confident Everton are in a strong position when it comes to resisting any offers for Barkley.
"What is very important is that if anything happens, it is our club that dictates how and when," he added.
"If we had a financial problem or were facing a financial disaster then we would not be in control of those aspects and I would be telling you: 'Look, we are in the lap of the Gods.'
"We are not in that situation at all. We are probably in the strongest financial position we have been for a long time.
"All we are going to make is football decisions. If we were going to lose a player it would be to end up with three or four replacements and in a stronger position. That is always the case.
"Ross is an icon for us. He represents everything we are trying to do this season, so even if a stupid offer arrived in January it would never affect us. It is important for us as a football club to show we are making the right football decisions.
"There is no question mark over Ross' future; he is in the best moment of his time and is everything we want a player to represent at Everton.
"There is not even a question mark against whether he is going to be here in February or not."
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