"Several factors brought on by the Syria crisis have caused a loss of more than $20 billion" since March 2011, Rashid Derbas said.
"Because of this, infrastructure planned to last for 15 years will now have to be changed in just two because of intensive use" due to the presence of 1.1 million refugees from Syria, he added.
He also cited the use of energy resources, primarily electricity, by refugees unable to pay for it.
Tourism has also been hit hard, Derbas said of some 500,000 tourists who used to arrive overland via Syria.
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He expressed regret that much of the international aid pledged to help Lebanon cope with the influx has yet to materialise.
"We have received just half of the amount promised for 2013 and only 44 percent this year," Derbas said.
Refugees now account for a quarter of Lebanon's population and cost Beirut $4.5 billion a year, Central Bank Governor Riad Salameh said in June.
Basing this estimate on a World Bank study, he said "the direct cost to the Lebanese state is around a billion dollars per annum, with an indirect cost of 3.5 billion".