A committee of the UN High Commissioner for Human Rights is assessing responses to a letter sent to the Dutch government early this year, the NRC Handelsblad reported.
Black Pete, or "Zwarte Piet" in Dutch, traditionally accompanies Saint Nicholas at a festival on the third Saturday of November, when he officially "arrives" in The Netherlands in a gift-filled boat from Spain.
The character is typically decked out in a gaudy medieval costume and afro wig, with his face painted black, prompting criticism in recent years of racial stereotyping.
Opponents say the character recalls when Dutch colonists exploited slaves, notably in the Caribbean colonies of Suriname and Curacao.
"According to information we have received... the character and image of Black Pete perpetuate a stereotyped image of African people and people of African descent as second-class citizens," said the letter, dated January this year and published Saturday on the NRC's website.
The letter by four officials of the Geneva-based UN rights body asked for a clarification from Dutch authorities.
"Please indicate to which extent your government has involved Dutch society, including African people... in the discussions regarding the choice of 'Santa Claus and Black Pete' as expression of cultural significance in the country," it said.
Emotions are flaring over the racially sensitive issue.
Amsterdam held a public hearing on Thursday during which 21 complaints about Black Pete were filed asking the Dutch capital to revoke the permit for this year's festival.
Mayor Eberhard van der Laan is to rule on the permit in early November, his spokeswoman Tahira Limon said.
But Black Pete's supporters called for the children's Saint Nicholas festival to go ahead, arguing that it has been part of a Dutch tradition dating as far back as the 16th century, with the Black Petes first appearing around the 1850s.
In a survey of 10,000 people published by the popular broadsheet De Telegraaf on Saturday, some 96 percent asked for a stop to the debate over Black Pete.
Some 66 percent said they would prefer that the entire Saint Nicholas festival be dropped rather than stripping it of the Black Pete character.
One respondent told De Telegraaf: "The 21 complaints are spoiling it for the rest of The Netherlands."