The 23-year-old, who can operate either in defence or central midfield, was part of his country's victorious EURO 2012 squad and featured in the group stage win over
"I'm very happy at Athletic," he told Spanish television channel Antena 3. "I have a contract until 2016.
"I have seen the newspapers and what it says on TV, but it is not always right.
"If you were to believe what is said I have already joined seven different teams, a different one each week. You have to ignore the rumours because they can affect you."
The club's policy of only selecting players from the Basque region engenders fierce loyalty and could be a trump card as it seeks to hold on to prize assets such as Martinez,
The restriction does not extend to the appointment of coaches, and speculation has this week surrounded the future of Argentinian Marcelo Bielsa after an angry confrontation with contractors carrying out work at the club's training ground and a subsequent disagreement with the board.
Martinez is hopeful the club has moved on from the incident and can get back to normal as it prepares for the new season.
"I'm not sure what happened with Bielsa, but the best thing for everyone is what is happening now, that everything is back to normal and the coach has devoted himself," he said.
"There has been tension but it has since subsided.
"Bielsa is among the three or four best coaches in the world, he is very good and you just have to see how we played this year."
Real Sociedad continues to hold the edge in the battle for a top-four finish in the Primera Division after a 2-1 victory at Sevilla.