Mexico's President has confirmed support for New Zealand's bid for a seat on the UN Security Council.
New Zealand has been campaigning for the seat in 2015 for several years against rival contenders Spain and Turkey.
After their bilateral meeting in Mexico City this morning, Mr Key thanked President Enrique Pena Nieto for confirming Mexico's support - a step that could help secure the support of other Latin American countries.
Three of the countries on Mr Key's Latin American trip have previously indicated support, but Mr Key said it was important to shore that up while on his visit. Usually countries do not publicly confirm who they support.
After the meeting Mr Key said Mexico's support underscored ongoing co-operation between the two countries on several international issues.
Mr Key also invited Mr Pena Nieta to visit New Zealand - a trip he is likely to combine with a visit to Australia.
The pair also agreed to further trade links - Mr Key said New Zealand exporters to Mexico currently faced 60 per cent tariffs on some goods.
"President Pena Nieto and I agreed the trade relationship between our two countries, while healthy, could be strengthened further."
He said the Trans Pacific Partnership - which both Mr Key and Mr Pena Nieto wished to be concluded by the end of the year - would help those companies looking to invest in Mexico.