Kirsten Johnson at Steven Kay's London legal offices said: "An application has been made to leave representation (at the Milosevic trial)".
"Until the court makes a decision, they will continue to be involved in the case," she added.
British laywers Steve Kay and Gillian Higgins were assigned to defend Milosevic on 2 September because judges at the UN war crimes' court in The Hague, Netherlands, ruled the former president's health was too fragile to go on representing himself.
Officially the lawyers cannot resign without the court's approval because they are court appointed.
It is not known when the court will rule on the application.
"We are entirely in the hands of the court," Johnson said.
In an appeals hearing against their own assignment, the lawyers told the court last week that they were unable to present a proper defence for Milosevic because he refused to cooperate with them.
"My team and me are unable to properly perform our function," Steven Kay said at last week's hearing.
Kay argued that Milosevic's right to represent himself should be restored.
"Who's running this court: the accused or the judges hired to do the work?"
Prosecutor, UN war crimes' court, The Hague
Prosecutor Geoffrey Nice urged the judges at the hearing not to give in to such pressure, asking: "Who's running this court: the accused or the judges hired to do the work?"
Milosevic has been on trial before the UN court for over 60 charges of genocide, war crimes and crimes against humanity since February 2002.
The charges relate to the genocide and war crimes that accompanied the wars of Yugoslavia, from 1992-95 in Bosnia, 1991-95 in Croatia and 1998-99 in Kosovo.
He also faces charges of genocide relating to the Sebrenica massacres, which have been called the worst atrocity on European soil since World War II.
More than 200,000 people who were massacred in the Balkans wars were Muslims, including women and children.