30 January 2015
Last updated at 10:47 GMT
First Minister Carwyn Jones was dragged into a row over the Falkland Islands on a previous visit by Alicia Castro
The Argentine ambassador says the UK government should open a dialogue over the future of the Falkland Islands.
At a function in Cardiff to mark 150 years since a Welsh settlement was founded in Patagonia, Alicia Castro said the landmark should spur the government into action.
She said Argentina had important historical links with Wales.
The Foreign Office said it would not negotiate away the rights of the Falkland Islanders behind their backs.
The function marked the launch of a programme of events to commemorate the 160 settlers who travelled from Wales to Patagonia in 1865.
'Controversy'
"We hope that this makes an example and we hope that the government of the United Kingdom opens a dialogue with the government of my country," she said.
On a visit to Wales in 2014, Ms Castro said the Welsh settlers' integration into Patagonia disproved "propaganda" about Argentina's intimidation of people living on the Falkland Islands.
It was a point she reiterated on her latest visit, saying: "The controversy that we have [with the Falklands] has nothing to do with the people.
"We fully respect the British descendants and I think that the Welsh people living happily in Patagonia is the most perfect example of cooperation and integration."
A Foreign Office spokeswoman said: "This is not a bilateral issue to be negotiated between the UK and Argentina - the Islanders' wishes are paramount.
"We want to have a full and friendly relationship with Argentina, as neighbours in the South Atlantic and as responsible fellow members of the G20, but we will not negotiate away the rights of the Falkland Islands' people against their will or behind their backs.
"There are three parties to this debate, not just two as Argentina likes to pretend."