Argentina has announced that any ship sailing between it and the Falkland Islands will now need a government permit.
The BBC reports Argentina is becoming increasingly agitated at the forthcoming start of oil drilling in Falkland Islands territorial waters.
Argentina claims sovereignty over the territory and invaded the islands in 1982. Britain sent a taskforce to regain control over the Falklands.
Although that conflict was 28 years ago, tensions over the islands - which Argentina calls the Islas Malvinas - remain.
Earlier this month, Argentina protested to Britain about the start of the oil drilling work there, which is expected to begin in the first half of this year.
The announcement on the new rules on ship movements was made by Argentine cabinet chief Anibal Fernandez.
He said it also applied to boats which were only travelling through Argentine territorial waters, and those going to other islands in the South Atlantic - South Georgia and the South Sandwich Islands.