Footage on state TV showed a large cylinder plunging from a crane on a moored vessel, causing a violent explosion of yellow gas.
The death toll rose to 10, Faisal al-Shaboul told AFP, revising an initial toll of five killed.
Prime Minister Bishr Khasawneh and Interior Minister Mazen al-Faraya headed to the site of the accident, state media reported.
Civil defense spokesman Amer al-Sartawy had earlier reported that 234 people were injured after the tank filled with toxic gas fell.
“Specialists and the hazardous substances team in the civil defense are dealing” with the incident, Sartawy added.
According to Jordanian official sources, Aqaba’s southern beach was evacuated following the incident.
Jordan’s Aqaba port is the country’s only marine terminal and a key transit point for a vast portion of its imports and exports.