A court order was made in October 2018, requiring King Albert II to provide a sample to resolve the long-running court case.
He is yet to comply with the order. On Thursday a Brussels court ordered the 84-year-old to attend an appointment and provide a sample in the presence of a justice official.
The retired monarch, who abdicated six years ago, is challenging the most recent ruling, according to a judicial source who spoke to the Reuters news agency.
Claims that Delphine Boel is the former monarch’s daughter first emerged in 1999, when an unauthorised biography about Queen Paolo, King Albert’s wife, was published.
Ms Boel, an artist, claims that King Albert had a long-running affair in the 1960s with her mother Sybille, Baroness de Selys Longchamps.
Her mother has previously spoken about the 18-year-long affair.
Ms Boel was born in 1968 and raised in London, where her mother moved for privacy reasons in 1976.
King Albert, who has no formal public role, has acknowledged that he and Queen Paola have previously had marital difficulties.
He has never publicly denied being Ms Boel’s father but has fought her claim for recognition for over a decade.
The artist wrote a book detailing her story in 2008.
“You are responsible for the child you produce. You do not abandon it,” she wrote at the time.
“That is what my father has done”.
A court-ordered paternity test has already established that the 50-year-old is not the biological daughter of Jacques Boel, her legal father.
King Albert has three children with his wife, all of whom are older than Ms Boel.
His son Philippe is the current king of Belgium.
Additional reporting by agencies