Martinez said that he will never stand in a player's way, but also insisted that he will never sell a player for less than he is worth.
The Spaniard believes that other clubs must respect the fact that they took a chance on the Nigerian by shelling out £2.5m on him as a 19-year-old from Crystal Palace.
"Victor's 21, he's got a year left on his contract and my chairman is always very clear," Martinez told The Mirror. "We would rather have Victor for a year rather than selling him under his value. We don't have to sell players, so we will never undervalue players.
"We will never stand in the way of players who want to move on to other projects - let's say a player who can move on and try and win the Premier League - but in football, and in life in general, if you want something, you have to meet the valuation. Until that happens, it's not an issue.
"Remember, we made a huge investment in Victor when he was 19 and in the Championship, which other clubs wouldn't. We will never undervalue one of the biggest talents in this league. Clubs must respect that."
Moses scored six goals in 36 appearances last season.