The Republic of Ireland international has reportedly attracted interest from the likes of Manchester United, Arsenal and Manchester City.
However, Toffees boss Martinez has insisted that those clubs would be wasting their time in any efforts to sign Coleman.
"We won't offer encouragement to any club over Seamus. He is on a long-term contract and we want to ensure we grow together and we need players like Seamus," Martinez is quoted as saying by The Mirror.
"Seamus has got a long-term contract. James and Ross are the same. But we want to reward them. That is something we will look at this summer."
Coleman, whose current agreement expires in 2018, joined Everton from Sligo Rovers in 2009.