Del Bosque beat Mourinho to the prize for 2012 after claiming 35 percent of the vote to 20 percent for the outspoken Real Madrid boss.
However, in an interview with Portuguese TV station RTP on Tuesday, Mourinho said that he had been informed that some of those who had voted for him, had their votes changed.
"It doesn't bother me at all," Del Bosque told radio station ONDA CERO.
"We are 48 hours from an important game against Finland and I am not worried about anything other than this.
"It is a subject that I have to keep my distance from. It is a childish thing. I don't want to even give the hint of a smile in case it is misinterpreted."
Mourinho's claims were, however, given some credence by Macedonia captain Goran Pandev.
The Napoli forward was managed by Mourinho during his time at Inter Milan and said he was one of those who contacted Mourinho to inform him of irregularities.
According to the list published by FIFA, Pandev had voted for Del Bosque as best coach, followed by Manchester City's Roberto Mancini and Borussia Dortmund's Jurgen Klopp.
"I voted for Mourinho, as I always would and then strange things have happened," he told La Sexta.
"I phoned Mourinho and I told him that, as captain of Macedonia, I voted for him, I don't know what then happened."
FIFA though have insisted that the full list of votes conducted by international captains, managers and journalists that they originally published is correct.