The closure of tunnels used to smuggle goods into the Gaza strip has cost the nation monthly losses of $230 million (170 million Euros), a Hamas official said Sunday.

The "closure of the tunnels has caused heavy losses to a number of sectors, including industry, commerce, agriculture, transport and construction, amounting to around $230 million monthly," said Hatem Oweida, Deputy Economy Minister for the Islamist movement Hamas, which governs the strip.

Essential materials have been smuggled from Egypt into Gaza for years through tunnels, bypassing Israel's blockade. However, the Egyptian army recently destroyed many of them after ousting president Mohamed Morsi of the Muslim Brotherhood, a Hamas ally.

Oweida said the coastal Palestinian territory relies on the tunnels to meet at least 40 percent of its construction and raw material needs.

Gaza's unemployment rate would likely hit 43 percent if official border crossings remain closed and the tunnels are destroyed, Oweida warned.

He added that "public revenues saw a decline after the closure of the tunnels and the tightening of the siege in the second half of 2013," which he said would impact Hamas' employment and temporary work programmes.

Israel first imposed its land, sea and air blockade on the coastal strip in 2006 after militants there seized an Israeli soldier.

It was further tightened in mid-2007 when Hamas took control of Gaza.