Her body was removed from her apartment this morning and a post-mortem examination is expected to take place in due course.
This photo relesead by Telam on June 07, 2018, shows Ines Zorreguieta, the youngest sister of Argentine-born Maxima Zorreguieta, now queen of the Netherlands, attending the baptism of Princess Ariane on October 20, 2007 in The Hague, Netherlands.
Dutch state-run news agency RVD said the queen was "very shocked and very upset by the news".
"It is presumed that it was a suicide", a spokesman of the Dutch government told the Argentinian newspaper, La Nacion.
"With our hearts and our thoughts we are with the queen and her family".
She was a civil servant who had been working for the Argentinian government since 2016, in an office that oversees social policies.
'I wish them all the strength they need to cope with this awful loss.
Between 2009 and 2011 she worked at the United Nations headquarters of Panama but returned to Argentina in 2012 after a breakup. Zorreguieta reportedly suffered from depression and was seeking psychological help. She has since canceled her forthcoming engagements including a state visit to Estonia, Latvia and Lithuania next week.
Their father, Jorge Horacio Zorreguieta, died a year ago in Buenos Aires at age 89.
She was a bridesmaid for her sister's 2002 marriage to then-Dutch Crown Prince Willem-Alexander, and goddaughter for the couple's youngest daughter, 11-year-old Princess Ariane.
Jorge Zorreguieta worked as agriculture minister during Argentina's brutal military dictatorship.
Queen Maxima, 47, has two other brothers, Martin and Juan, and three half-siblings, the BBC reported.