The message will be that Lebanon faces deeper isolation and economic devastation unless it forms a government committed to reforms, eliminating corruption and curbing the stranglehold of the Iranian-backed Shi'ite group, according to an administration official, a Western diplomat and regional government sources.

The U.S. delegation, led by Morgan Ortagus, deputy special envoy for the Middle East, will meet newly-elected President Joseph Aoun, Prime Minister-designate Nawaf Salam and Parliament Speaker Nabih Berri.

But the U.S. is seeking to curb the influence that Hezbollah will wield over it, in an attempt to capitalise on the pummeling that the group took in its war with Israel last year.

"It's important for us to set the tone for what we believe a new Lebanon should look like going forward," said the senior U.S. administration official, while asserting that Washington was not "picking" individual cabinet members but ensuring Hezbollah has no part in the government.

"There was a war and Hezbollah was defeated and they need to remain defeated," the official added. "You don't want somebody corrupt. It's a new day for Lebanon. Hezbollah was defeated, and the new government needs to match that new reality.