Hillary Clinton was urged to use a trip to New Zealand to highlight the United States' work in the Pacific region in order to counter Chinese influence, newly released emails show.
Thousands of Mrs Clinton's emails while she was US Secretary of State have been released.
Mrs Clinton is seeking the Democratic nomination for the presidential election next year, and has been caught up in controversy over her use of a private computer server for work emails.
Her opponents have claimed that the use of a private server during her time as secretary of state, from 2009 to 2013, put US security at risk.
The US state department has now released 4368 emails - some of which shed light on the superpower's relationship with New Zealand, and discussions about how it could use that as a way to counter Chinese influence in the region.
An October 27, 2010 email sent to Mrs Clinton by Melanne Verveer, US ambassador at large for global women's issues, includes for her information an earlier email from Ms Verveer to state officials about Mrs Clinton's three day visit to New Zealand in November, 2010.
During the visit New Zealand wants to announce a collaboration with the US that will increase women's political participation in the Pacific region, Ms Verveer states.
"I wanted to briefly share some thoughts on this formed during my last trip to China," Mrs Verveer writes to the officials, in an email she later forwarded to Mrs Clinton ahead of the New Zealand trip.
"It made the collaboration with NZ and Australia on deeper engagement with the Pacific Islands on women and development issues that much more compelling."
Mrs Verveer wrote that in Beijing she spoke at an international women's forum, organised by an organisation affiliated with the Chinese Communist Party, and noted "almost everyone I know of significance who works on women's issues from Southeast Asia, the Pacific and Africa in attendance".
"However, I did not see government reps from Europe or NEAsia. It appeared to me that the forum was targeted to engage countries and regions where China is expanding its influence.
"I know [Mrs Clinton] is going to give a policy speech in Australia during this trip. I hope that you will include our commitment to women in the Pacific Islands, especially through these proposed collaborations with Australia and NZ," the US ambassador at large for global women's issues wrote.
"As you know very well, the 12 Pacific Islands, although small in size, represent 12 votes in the UN. They long for our attention and collaboration. I think women's development issues are one ideal way to further our interests and engagement."
Another email to Mrs Clinton from an unnamed official, titled "welcome back!" and sent on November 9 and after her New Zealand trip, said the trip looked very productive.
"And thanks for embracing the women's initiatives in AU and NZ. Their governments were thrilled and the press was excellent. Lots of good work ahead."
Mrs Clinton's 2010 trip was hugely significant in terms of restoring full diplomatic relations with New Zealand.
While here she signed a new partnership document known as the Wellington Declaration, that covered areas of co-operation including non-nuclear proliferation, the Pacific, and Antarctica and the Southern Ocean.
The declaration is thought to have been proposed by Washington as a tangible symbol of the restoration of the relationship since its decision in 2007 to accept New Zealand's anti-nuclear stance as permanent.