Spain will seek to take its dispute with the UK over Gibraltar to the UN with the support of Argentina, according to Spanish media.

The Spanish foreign minister, José García-Margallo, is expected to propose that both countries present a "united front" over Gibraltar and the Falkland Islands, El País reported.

García-Margallo will sound out his Argentinian counterpart, Héctor Timerman, during a meeting in Buenos Aires next month as he prepares for a "180-degree turn in policy towards the colony", the newspaper said.

Such a move would be seen as an escalation in the diplomatic tensions surrounding the overseas territory.

Argentina has a two-year term as non-permanent member of the UN's security council and could potentially use its position to put discussions about Gibraltar on the agenda.

The country's president, Cristina Kirchner, used a meeting of the council this week to renew demands for talks over the sovereignty of the Falklands.

Spain is also considering the possibility of raising the matter of Gibraltar at the UN's general assembly or the international court of justice at The Hague, diplomatic sources reportedly told El País.

A Foreign Office spokeswoman said: "Our policy on Gibraltar has not changed and is consistent with our policy on other overseas territories. Self-determination matters more than territorial integrity.

"The people of Gibraltar have repeatedly and overwhelmingly expressed their wish to remain under British sovereignty."

A British warship will visit Gibraltar later this month in what the Ministry of Defence (MoD) says is a "long-planned" training deployment.

Political tensions in the region flared after the British territory began work on a concrete reef in the Mediterranean, which Spain claims will destroy fishing in the area. Madrid responded by beefing up border controls and suggesting that a €50 (£43.30) fee could be imposed on every vehicle entering or leaving the territory through its fenced border with Spain.