Residents in northern Lebanon say that rebels pose as refugees to cross the border, and are arming members of the refugee community in Lebanon to fight in Syria. The minister, Marwan Charbel, has said Syrian rebels have set up training camps in Lebanon.
In addition, members of the rebel Free Syrian Army have used Lebanon's mountainous terrain to regroup before staging attacks on the Syrian army across the poorly demarcated border.
"What is concerning me is the security situation," Charbel said at a joint news conference with the United Nations Development Program. "Who is exploiting (the Syrian refugees)? Who is arming them? We are not controlling them."
Although the uprising against Syrian President Bashar Assad is almost two years old, the flow of refugees is accelerating and the number in Lebanon has doubled in the last three months, to 320,000.
Beyond the security concerns, popular resentment is building as resources are stretched and jobs are being taken.
Lebanon, a country of only 4 million, now hosts a million Syrians in all, if self-supporting families and manual laborers are included.
The issue of refugees is especially sensitive in Lebanon, whose own 15-year civil war was triggered in part by tensions over Palestinian refugees who came after the creation of Israel.
Most of the Syrian refugees in Lebanon live with host communities rather than in camps like those in Jordan and Turkey.
The government and UNDP launched the "Lebanese Host Community Support Program" on Thursday in an attempt to raise funds for refugees and lessen the burden on host communities.
They did not say how much was needed but Lebanon, which already suffers power cuts and regular strikes, asked for $180 million in January to help care for the refugees.
Social Affairs Minister Wael Abu Faour said funds provided so far were insufficient and that the Syrian displacement could lead to violence in Lebanon if donor countries did not provide funds for water services, food subsidies and other projects.
BEIRUT (Reuters) -- Lebanon's interior minister said on Thursday that refugees who have fled from the war in neighboring Syria have become a threat to Lebanon's security because of the suspicion that many are in fact rebel fighters.