CBS News Correspondent Robert Berger reports the Israeli government is concerned about the war crimes allegations against Sharon, stemming from his role in the massacre of Palestinians during Israel's invasion of Lebanon in 1982.
A Belgian newspaper said on Saturday the Brussels Public Prosecutor's office had ruled that a complaint against Sharon accusing him of crimes against humanity was admissible.
An Israeli investigator of war crimes, says this case should not be pursued.
"The effort is misplaced," said Ephraim Zuroff. "I think that this smacks of politics more than anything else."
Israeli officials say going after Sharon tarnishes the efforts to bring real war criminals to justice.
A 1983 Israeli state inquiry found Sharon, then the defense minister, indirectly responsible for the massacre by Israeli-backed Christian Phalangist militiamen.
The Israeli army had allowed the militiamen to enter the camp, ostensibly to search for Palestinian gunmen.
Pressure is also mounting on Sharon over the events of nearly 20 years ago because of the precedent set by the transfer of Milosevic, the former Yugoslav president, to The Hague to face charges of crimes against humanity.
A lawyer for Sharon dismissed the moves in Brussels as a poliical stunt.
"We are very, very far from a court case," the lawyer, Dov Weisglas, told Israel's Army Radio.
"The Belgian court has not found anything. What happened is the complaint...was sent by the prosecutor general to an investigating judge so he can open an investigation. Only if or when this investigation finds enough evidence for an indictment will an indictment be issued to a court."
The Israeli newspaper Yedioth Ahronoth said on Sunday that Israel's political and judicial establishments were anxiously monitoring developments in the case in Belgium.
It quoted diplomatic sources as saying the government had sent representatives to Brussels to observe the developments first hand. The report could not be confirmed independently.
Sharon is expected to visit Europe later this week, after postponing a trip to Belgium, Germany and France last month at short notice.
Although details have not been announced, political sources say Sharon is likely only to visit France and Germany, although Weisglas said there was "no concern" about him visiting Belgium.
The controversy over the massacre has resurfaced at a difficult time for Sharon.
He presides over a broad coalition government which is trying to quell a nine-month-old Palestinian uprising against Israeli occupation in the West Bank and Gaza Strip. About 600 people have been killed in the violence.
Under fierce international pressure to give peace a chance, he is trying to stick to what he calls a policy of restraint so that a shaky cease-fire can hold and the two sides can move on to confidence-building measures and eventually revive peacemaking. Some right-wingers want him to strike hard at the Palestinians.
Controversy over the 1982 massacre was revived by a BBC program broadcast on June 17 which asked whether Sharon should be brought to trial.
A legal expert told the BBC that he had "no doubt whatsoever" Sharon was indictable as a war criminal. Israeli officials said the program was scandalous and anti-Semitic.
The day after the program was shown, the complaint against Sharon was filed in Belgium by Chibli Mallat, a Lebanese lawyer representing 23 Palestinian and Lebanese plaintiffs.
The complaint was filed under a 1993 law allowing Belgian courts to prosecute foreign officials for human rights violations committed outside Belgium.
Human Rights Watch, a leading U.S.-based human right group, increased pressure on Sharon by calling days later for a criminal investigation.
©MMI Viacom Internet Services Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Reuters Limited contributed to this report