PANAMA CITY (AFP) - The Panama Canal will temporarily limit the size of ships using the waterway due to a drought caused by the El Nino weather phenomenon, authorities said Friday.

The Panama Canal Authority said the maximum ship draft will be cut to 11.89m from September 8, affecting 18.5 per cent of vessels that normally transit the link between the Atlantic and Pacific oceans.

A ship's draft is its depth in the water, and changes as the vessel becomes heavier or lighter.

The canal authority said further restrictions could be imposed on September 16 if weather conditions do not change. The maximum draft of vessels would be cut to 11.73m.

Canal administrator Jorge Quijano said the month of June and the first half of July was the driest period in 102 years.

As a result, water levels in the lakes that feed the canal have dropped. The canal's locks can usually accommodate ships with a draft of up to 12m.

Dry weather conditions in March 1998 saw authorities take similar measures.