The action began on shift C which started at 11pm and continued into this morning.
The protest actions stem from ongoing wage negations which have stalled for some time.
Representing union the Seamen and Waterfront Workers Trade Union (S.W.W.T.U.) and Port Authority officials held wage negotiations yesterday.
S.W.W.T.U. President, Michael Annisette, in a News Power Now interview says union officials went into the negotiations with an open mind.
Operations affect by the shutdown include the vessel, yard, gate and shed departments.
Mr. Annisette says the decision to protest did not take place over night since workers have been under strain for a while.
Seamen and Waterfront Workers Trade Union President, Michael Annisette
Operations affect by the shutdown include the vessel, yard, gate and shed departments