Builders working on an expansion of the Panama Canal said Tuesday they planned to have the refit completed by April 2016 despite the discovery of water leakage from fissures in one of the locks.

The third set of locks "has entered its countdown phase," the Grupo Unidos Por el Canal consortium, responsible for the expansion project, said in a statement.

The 80-kilometer (50-mile) canal, completed in 1914 to offer a short cut and safer journey for maritime traffic between the Pacific and Atlantic oceans, is undergoing a refit to triple its capacity.

"The project is expected to be completed in April 2016," the statement said. That would be 1.5 years past the original target date.

Almost all of the work has been completed, and structural and systems tests "are bringing optimal results."

According to the GUPC, the 16 massive sliding gates of the new locks "are responding positively to all electromechanical tests."

The statement comes weeks after alarm bells rang when fissures were found on the canal's Pacific locks, where water was filtering in through a concrete wall.

The GUPC said the fissures would be repaired by strengthening the lock walls with steel.

"From a technical point of view those fissures should not delay the handover of the new locks because they were produced during a period of extreme tests," said Olmedo Garcia, head of the Panama Canal Institute, part of the University of Panama.

At least three more months of testing will be carried out before navigation tests begin, the statement said.

The consortium expanding the canal is led by Spanish construction group Sacyr, and includes Italy's Salini Impregilio, Belgium's Jan de Nul and Panama's Constructora Urbana.

The consortium overran its initial $5.25-billion budget, leading to financial disputes with the Panama Canal Authority, the Panama government agency charged with operating the canal.