The two players have been linked with moves away from Goodison Park but Martinez says that the club has received "no firm interest" in either star.
It is believed that Belgian midfielder Fellaini has a £22m release clause that expires on July 31.
Baines has also been linked with Manchester United and there were reports earlier in the summer that the champions had a £12m bid rejected for the left-back.
"I wouldn't want to stop the speculation, I do think the speculation is healthy," Martinez said.
"If we've got clubs talking about our players, I'll take it as a compliment because the players have been impressing and doing really well.
"But we are in a great position financially and we want to start the season with the best possible squad that we have, and for that we have to work extremely hard."
Everton have made four signing so far this summer. They brought Barcelona youngster Gerard Deulofeu in on a season-long loan after bring former Wigan players Arouna Kone and Antolin Alcaraz and Atletico Madrid goalkeeper Joel Robles, who was also at the DW Stadium last season, to Goodison Park.