Officials running the Panama Canal said Wednesday they have lifted restrictions on the depth of ships passing through that had been imposed since April because of low water levels caused by severe drought.

The start of the tropical rainy season had brought the water back up, meaning the ships' maximum draft -- the distance from the waterline to the bottom of the hull -- was restored to the usual 12.04 meters (39.5 feet), the Panama Canal Authority said in a statement.

Starting April 18 the draft had been progressively trimmed in 15-centimeter (5.9-inch) increments to ensure vessels could transit through the canal without scraping bottom.

That measure had been imposed because of three years of drought worsened by the El Nino weather phenomenon that dries out parts of Central America.

Around 35 to 40 cargo ships a day pass through the canal, which accounts for five percent of the world's maritime commercial traffic.

On June 26, Panama holds an inauguration ceremony for the completed canal, which has been broadened over the past nine years to take larger cargo ships.