Biden and Xi: The world leaders Jacinda Ardern can't 'simply drop a WhatsApp' to raise China-Solomon Islands pact concerns

Sustainability of supply chains and the planet were the focus of Prime Minister Jacinda Ardern's second day in Singapore.

New Zealand signed agreements on both fronts. But it was another agreement between China and the Solomon Islands that caused concern. 

Singapore's shores are stacked with ships lining up to get unloaded - 250,000 get processed every single day. 

"Singapore is a logistical expert," Ardern commented on Wednesday. 

When COVID-19 slows the port down, the whole world suffers. The Prime Minister paid the port a visit to announce a joint working group to shore-up supply chains. 

"COVID has taught us many, many lessons but the impact that supply chain constraints can have on economies, particularly smaller economies, was one of them," Ardern said. 

Sustainability of supply chains was a focus of the day, and sustainably of the planet, with the Government signing up for more sustainable aviation.

"Climate change, for both our nations, represents an existential crisis which we must address," Ardern said in a speech at a business breakfast. 

It's not just fossil fuels New Zealand needs to depend on less. We've got a trade addition - to China. 

Dairy giant Fonterra launched its competitor in the cultured milk market at the business breakfast. 

"We will continue to invest in the Chinese market but it's an 'and' story here," Fonterra CEO Miles Hurrell told Newshub. "How do we support growth in other markets such as Southeast Asia and Japan at the same time?"

But despite branching out, New Zealand's biggest company is sticking with China. 

"China is still a very important market," Hurrell told Newshub. 

China - a very important market engaging in very worrying behaviour. It has reportedly just signed its long-suspected security pact with the Solomon Islands. 

"Simply put, there is no need for this agreement that they have signed," Ardern said. 

It's sparking concern that China will look to throw its military weight around in the region. 

"The broad nature of the security agreement leaves open the door for the deployment of Chinese military forces to the Solomon Islands," US State Department spokesman Ned Price said.

"We believe signing such an agreement could increase destabilisation within the Solomon Islands and will set a concerning precedent for the wider Pacific Island region."

New Zealand and Australia are making it clear we don't want that in our backyard. 

"There is a lot of influence going on in the Pacific and there is a lot of pressure being placed on other Pacific countries around our region and what they need to understand is that I am going to work with them," Australian Prime Minister Scott Morrison said. 

Ardern added: "We must draw clear lines where we have areas of concern and the militarisation of our region is a very clear line."

But Ardern is going to wait for formal sit-downs with the super-powers - US and China - to raise those concerns leader to leader.

"There are some leaders where you simply don't drop a WhatsApp to. I would consider [Chinese] President Xi and [United States] President Biden to be amongst those," Ardern said. 

The threat of Chinese warships in the Pacific is no doubt now high on the agenda for the Tokyo leg of the trip on Thursday.