The decision comes after row within the secretive committee that awards the Nobel Prize in Literature over sexual harassment allegations prompting a rare intervention in public life by King Carl XVI Gustaf.
Sweden's king will change the arcane rules of the Swedish Academy, which picks the winner of the Nobel Prize for Literature, making it possible to bring in new members after a controversy has seen several members resign.
"I intend to amend the Swedish Academy's statutes so that it is made clear that it is possible to leave the Academy at one's own request," King Carl XVI Gustaf said in a statement on Wednesday.
The head of the Swedish Academy stepped down last Thursday after criticism of how the institution handled a probe into allegations of sexual misconduct by a man married to one of its members.
Resignations after allegations
The Academy has been mired in controversy since last fall over its handling of allegations of sexual misconduct by a man married to a member of the Academy.
Five of the 18 members, including the permanent secretary, have stepped down over the past few weeks in an apparent power struggle.
Two members left years ago and the changes now mean the vacant seats can be filled by new members.
"It was the wish of the Academy that I should leave my role as Permanent Secretary," Sara Danius, who has held the post since 2015, told reporters.
"I have made this decision with immediate effect."
Concerns over image of Nobel Prizes
The public row and defections from the Academy have raised concerns that the image of the Nobel Prizes and Sweden's reputation abroad could suffer.
"It has already affected the Nobel Prize quite severely and that is quite a big problem," Danius said.
The allegations of sexual assault and harassment were made against Jean-Claude Arnault, the husband of Academy member Katarina Frostenson who also stepped down on Thursday.
In an emailed comment to Reuters news agency, Arnault's lawyer, Bjorn Hurtig, said his client rejected all allegations against him.
"Jean-Claude Arnault rejects all claims of criminal activity and he rejects other allegations that have been made against him," Hurtig said.
State prosecutors opened a preliminary investigation into the incidents, but said last month some parts of the probe had been shelved due to a lack of evidence and the statute of limitations having passed for some of the incidents.
However, prosecutors said the investigation related to some incidents was continuing.
The secretive Academy, established in 1786 by King Gustav III, is not a government agency and its statutes say once a member is elected he or she cannot step down.
However, as the Academy's patron, the king can make amendments to the statutes.
The changes are a rare intervention in public life by Sweden's king, who wields no formal power.