The Spaniard has already ruled out the midfielder’s exit this summer but caused speculation over the player’s future beyond the end of next season after suggesting that "Everton is the perfect place for him for the next 12 months”.
However, Martinez claims his comments were based on Barkley’s improvement at Goodison Park and maintains the 20-year-old, who is in Roy Hodgson’s England squad for next month’s World Cup, is a key part of the club’s plans.
“It was about Ross’ development and how the next 12 months are crucial," Martinez told Liverpool Echo.
"This is a vital period for him to fulfil his potential and the environment where he will be is everything. The only place is Everton.
“We want him for the long term but these 12 months are crucial.”