It's never smooth sailing when it comes to international diplomacy, but this week has the potential to be particularly rocky. The Prime Minister is heading overseas for two major events on the political calendar, the East Asia Summit, and the Pacific Islands Forum.

The tension will be thick in the air from the get go, thanks to the recent ruling on the South China Seas dispute. The International Tribunal for the Law of the Sea dismissed China's claim to the territory, backing the Philippines. China hasn't accepted it, leaving the relationship frosty, and an elephant in the room for the East Asia Summit.

New Zealand is caught in the middle. We have close trade ties with China, which is our major market for milk, and China has made it clear in the past that it will use those trade links to apply pressure. But the Philippines has the clear moral high ground.

If that wasn't enough for the Prime Minister to navigate, John Key will also have the TPP, and Helen Clark's bid for the UN on his mind. Political heavyweights will be in attendance, including the US President Barack Obama. Key has already made it clear that he intends to use the opportunity to lobby for Helen Clark to become the next UN Secretary-General.

What he's left unsaid is that he'll also be lobbying to save the TPP, which is in danger of becoming dead in the water. Years of wrangling has finally seen all countries agree on the terms. But now both of Obama's possible replacements, Hillary Clinton and Donald Trump, are campaigning on being opposed to the controversial deal. They could scrap it, rather then officially signing it into law.

If the US is out, everybody else may well follow suit. The TPP would fall at the last hurdle. Key's only hope is to convince Obama to rush the trade deal through Congress in his last days as President.

So between the handshakes and fancy dinners, John Key is likely to find himself making a few waves. Because the alternative is watching the opportunities for New Zealand, dry up.