New Zealand's influence on the world stage has surged in the last year thanks to Jacinda Ardern's leadership, new analysis suggests.

The Asian Power Index is an analytical tool released yearly by the Lowy Institute which ranks 25 countries based on their power in the region.

New Zealand came in at number 12 with a score of 19.9, which classifies us as a "middle power" along with nations like Australia, South Korea and Thailand. We scored one point higher than last year, making us one of the index's "most improved" countries alongside Malaysia and Vietnam.

Prime Minister Ardern was named the fourth most influential leader in the Asia-Pacific region for her "ability to advance her country's diplomatic interests globally".

Lead researcher Herve Lemahieu said our international influence has increased largely because of effective leadership, specifically the strong connections Ardern has forged with other leaders since she came to power.

"You should never underestimate the capacity of leaders to shape their country and advance their foreign policy interests," he told the Sydney Morning Herald.

While New Zealand benefited from our leadership, Australia has fallen in its diplomatic standing because of its "political infighting" and notorious revolving door of Prime Ministers which has seen six different people in the role in the last decade.

But both countries are still rated as "resilient powers" thanks to our strategic geographical locations, and have both benefited economically as a result of the altered Trans Pacific Partnership.

The US and China are locked in a battle of the superpowers, ranking first and second respectively. While the US's score remains unchanged since last year, China's has grown, narrowing the gap between them to just 8.6 points.

Lemahieu says the Trump administration's focus on trade wars has weakened its influence in the Asian region and undermined its network of economic relationships.

The Asian Power Index awards its scores based on eight factors: economic resources, military capability, resilience, future resources, diplomatic influence, economic relationships, defence networks and cultural influence.

Newshub.