In total, 21 members of the triumphant squad from the summer have been joined by a further 18 players, who announced their decision via a statement on Friday afternoon.
The Spanish football federation, who had been due to name their squad on Friday afternoon for matches against Sweden and Switzerland later this month, have now delayed that announcement until further notice.
The Spanish players have taken the stance in the fallout from the World Cup final, where the former president of the Spanish football federation, Luis Rubiales, kissed Jenni Hermoso.
The Spain forward said the kiss was not consensual and Rubiales appeared in court on Friday in Madrid after being accused of coercion and sexual assault. He denies any wrongdoing.
Rubiales resigned as president last week, while head coach Jorge Vilda has also gone, and it was thought that could be enough to tempt the Spain players back - who originally announced last month they were going on strike.
But in their statement today the 39 players explained they are still yet to see enough changes from the Spanish football federation.
The statement, which includes the signatures of star names such as Hermoso, Alexia Putellas, Olga Carmona and former Manchester United player Ona Batlle, said: “Today, as we have transmitted to the RFEF, the changes that have occurred are not enough for the players to feel in a safe place, where women are respected, where there is a commitment to women’s football and where we can give our maximum performance.
“The players of the Spanish team are professional players, and what fills us most with pride is wearing the shirt of our team and always leading our country to the highest positions.
“For this reason, we believe that it is time to fight to show that these situations and practices have no place in our football or in our society and that the current structure needs changes. We do it so that the next generations can have a much more equal game that we all deserve.”
The statement calls for a restructuring of the women’s football department, the federation’s presidential cabinet and general secretariat, the communications department and the integrity department.