It also follows Foreign Affairs Minister Nanaia Mahuta earlier this year expressing New Zealand's discomfort with using the Five Eyes intelligence-sharing network - which includes Australia, New Zealand, Canada, the US and UK - to criticise China on human rights. 

Mahuta and Ardern have both reaffirmed New Zealand's commitment to the Five Eyes since - but it hasn't stopped commentators suggesting reluctance to criticise China due to New Zealand's heavy reliance on the Asian powerhouse for trade. 

For all the speculation though, Morrison firmly stated on Monday he does not believe New Zealand has sold its sovereignty to China.

"People are always trying to divide Australia and New Zealand - all over the place!"

Without specifying who, he said there are "those from afar" who would seek to divide Australia and New Zealand. 

"I think as great partners, friends, allies and indeed family, there would be those far from here who would seek to divide us and they will not succeed, because as we've stood resolutely together on the values and principles that Australians and New Zealanders have stood for and indeed fought for, that will continue to be the case. 

"Partnering successfully, as we have always done, whether it's the Five Eyes... whether it's in the OECD or multilateral forums or the World Trade Organisation or indeed the work we've done through the World Health Organisation where we share very strong views, we will continue to work together in that way.

"I have no doubt there would be those who would seek to undermine Australia and New Zealand's security by seeking to create points of difference, which are not there."

Ardern said New Zealand has always stood firmly by Australia. 

Morrison was asked to elaborate on who was trying to divide us.

"People are always trying to divide Australia and New Zealand - all over the place!" he said, looking over at Ardern, who grinned. "They will not succeed."

Ardern refuted the suggestion New Zealand is "doing anything other than maintaining a very principled position on human rights issues, on trade issues, as they relate to China, and in fact I think you'll find very little difference in many of the messages that we've been sending relative to Australia." 

She also rejected the suggestion New Zealand relies on Australia too much. 

"In my very strong view we carry responsibility for ourselves to ensure adequate investment in our Defence Forces and equally that we carry our weight as a member of the intelligence and security community.

"Having said that, we have always operated at a regional level where we support one another. There will be parts of the Pacific for whom we will be, for instance, better placed to engage in search and rescue, to engage in fisheries monitoring, to engage in monitoring trade sanctions than Australia, and vice versa. 

"We work together, but I reject any suggestion that we don't carry and deliver on our behalf and towards the international community."

Morrison agreed with Ardern. 

"Australia and New Zealand obviously have different capabilities in these areas and we have different programmes, but we have interoperability which is, I think, incredibly important. That interoperability has been on display in so many theatres of conflict in peace-keeping and emergency response all around the world, and particularly in our own region.

"Australia is continuing to increase our investment in these areas with our capability. We see this as very much in our national interest and we believe Australia acting in this way provides great stability and support to the region. 

"We each have different jobs to do, we each have different capabilities that we bring; it's our job as Prime Ministers to ensure that comes together in the best fit possible for the security of our own nations and our own national interests but also in the broader family role that we have across the Pacific."