"The United Nations Security Council should add M23 leaders, as well as Rwandan officials who are assisting this abusive armed group, to the council's existing sanctions list," Human Rights Watch said in a statement
"The M23's unrelenting killings and rapes are bolstered by the military support Rwandan commanders provide the rebel armed group," said Clementine de Montjoye, Africa researcher at the New York-based rights monitor.
HRW said it had "documented eight unlawful killings and 14 cases of rape by M23 fighters."
A 46-year-old woman was raped in February and her 75-year-old mother shot dead after she refused to have sex with the M23 fighters.
"As they were raping me, one said: 'We've come from Rwanda to destroy you,'" she said.
The DRC accuses Rwanda of backing the M23. Despite denials from Kigali, independent United Nations experts and several western nations, including the United States, agree with Kinshasa.
However HRW also said groups fighting the M23, with which the DRC government "collaborated," were also guilty of rape.
The Tutsi-led M23 has captured swathes of territory in DRC's North Kivu province since taking up arms in late 2021 after years of dormancy, with over one million people displaced by the fighting.
Kigali dismissed the HRW allegations.
"Rwanda is not going to be intimidated by these campaigns of disinformation and distractions from ongoing regional peace efforts," government spokeswoman Yolande Makolo told AFP.