The Port Authority however said that it successfully dealt with the incident.

Namely, operations were immediately ceased by both vessels and on receiving the report from C Rock, the GPA immediately launched its oil spill response emergency plan.

"It is estimated that between 50- 100 litres of fuel went into the sea but this was recovered very quickly by the oil spill responders and clean up operations on both vessels are currently underway," GPA said in a statement.

The GPA has opened a formal investigation into this small incident.

J Manuel Tirado, CEO and Captain of the Port (Acting) thanked all parties involved for their quick response in this incident and commented that the quick actions of both vessels and the oil recovery team resulted in the oil spill being contained with minimum impact on the environment.