Twenty-six-year-old Republic of Ireland right-back Coleman has been persistently linked with Manchester United in recent transfer windows.
And former Red Devils and Ireland full-back Denis Irwin was this week quoted as saying: "I think for him (Coleman) to be potentially world-class - and this is no disrespect to Everton - he probably has to move to a club that plays regularly in Europe."
Asked about those comments at a press conference on Tuesday, Martinez said: "He (Irwin) is making a judgement about a player who is very important for us.
"I still think Seamus Coleman can develop and progress with Everton.
"At the moment he is enjoying his football, I think he has an important role in our side and I think this is the best place for him to develop and fulfil his potential.
"He is a world-class footballer in the way he performed last season."
Everton, fifth last season, are currently 12th in the Barclays Premier League.
They are out of both domestic cup competitions, but, in what is their first continental campaign in five seasons, they have reached the last 32 of the Europa League - a tournament which has a place in next term's Champions League on offer for the winners.
Source : PA
Source: PA