Concerns are mounting in New Zealand as the Cook Islands' prime minister travels to China this week to sign agreements without properly consulting with New Zealand, despite the two nations' constitutional ties.

Diplomatic tension between the Cook Islands and New Zealand is growing. Here's what it's about, what China has to do with it, and why it matters.

The New Zealand Government says the Cook Islands has failed to properly consult it on proposed agreements Cook Islands Prime Minister Mark Brown will be signing in China this week. Brown has now left for China without further consultation,

There is no need for New Zealand to sit in the room with us,' Premier Brown says, referring to China ties, upcoming deal with Beijing - Anadolu Ajansı

New Zealand expressed renewed concern on Monday about the Cook Islands' prime minister travelling to China this week to sign agreements without properly consulting with Wellington despite the two nations' constitutional ties.