Argentina’s transport workers’ union says it will boycott ships flying the British flag because of the dispute over the Falkland Islands.

The union – which includes dock workers – said the measure would apply to all UK vessels reaching Argentina.

It is not clear how much impact the boycott will have.

Tension between the UK and Argentina over the Falklands has been rising in recent months as the 30th anniversary of the Falklands war approaches.

“We have resolved to boycott any ship with the British flag, or with the lying and invented flag of the Falklands, or with any flag of convenience which the British pirates use,” the Argentine Confederation of Transport Workers said in a statement.

The announcement is the latest in a series of measures aimed at pressing Argentina’s claim to sovereignty over the islands, which it calls the Malvinas.

In December, the South American trading bloc Mercosur closed its ports to ships flying the Falkland Islands flag.

And last week Argentina took its case to the UN general assembly, where it accused the UK of “militarising” the region and sending a nuclear-armed submarine to the South Atlantic.

The UK government has dismissed the claim of militarisation as “absurd” and says its defence posture in the Falklands has not changed.

It says there can be no negotiations on sovereignty as long as the Falkland Islanders wish to remain British.