Twin earthquakes that struck northern Venezuela have dealt a potentially devastating blow to an economy already on the brink, raising fears of a prolonged setback to the country's fragile recovery under its US-backed interim government.

A 7.2-magnitude earthquake and a 7.5-magnitude were less than a minute apart, said the U.S. Geological Survey. The second earthquake was the largest to hit the country since 1900.

Several earthquakes shook Venezuela's capital of Caracas on Wednesday afternoon,witnesses reported.

US Geological Survey estimates 44 per cent chance fatalities could exceed 10,000