The Prime Minister expects the vacancy caused by the looming departure of Pascal Lamy as WTO boss to be one of the issues up for discussion among the major Asian political leaders, the two Australasian leaders and the United States President (assuming the US Secretary of State is not deputed to take the President's place) in Phnom Penh.
In a briefing to a top-level business audience in Auckland last week, Key suggested that Groser's expected candidacy already had informal support from some major world leaders.
The Government was conscious of how big the challenge was. And he cautioned realism about the probability of success.
"It is a consensus agreement and there are many obstacles you can point to ... but he is without doubt in our view the best candidate in the world and he has a wide range of support."
So why pick Groser?
On his side is the fact that he is highly experienced, sharp and insightful and, importantly, can marry the big-picture political realities with the technical competence to get trade negotiations through thorny periods.
This was evidenced when he chaired the WTO's agriculture talks during an earlier part of the Doha round while occupying the role of New Zealand's Geneva-based ambassador to the WTO. Four years as New Zealand's trade minister has given him additional cachet at the highest political levels.
He has also operated as an interlocutor for the G20 on economic issues and is playing a significant role in climate change negotiations.
The problem is that some emerging countries see New Zealand as part of the wealthy nations' club. It doesn't help that former New Zealand Prime Minister and Trade Minister Mike Moore has already had a go in the role. Why give the Kiwis another turn when it really is our turn?
Plus he would be succeeding Lamy - a highly intellectual Frenchman who was previously the EU's trade commissioner.
Groser has yet to formally declare his candidacy for the director-generalship role. But when I broke the story of his intentions in the Herald on August 29 he did not demur.
In fact, this would have been absurd given it had been an open secret in the top echelons of the New Zealand international trade fraternity since late last year.
From Groser's viewpoint, it would be the pinnacle of a long and distinguished career in global trade.
His colleagues - both locally and internationally - recognise that. It probably goes without saying, so too does Groser.
Groser's support appears to be broadbrush.
US Trade Representative Ron Kirk is said to admire his abilities. So too, Indonesia's Gita Wirjawan. China also is said to appreciate his prowess.
These nations are in the camp that wants the WTO round finished.
Interestingly, Lamy believes his successor should be picked on the basis of competence alone.
He doesn't believe the role should be rotated between countries and regions.
Emerging countries are claiming it's "their turn" to have their player in the top Geneva role. Particularly as the top jobs at the World Bank and IMF went to an American and a European.
But Lamy indicated to Reuters recently that the WTO job was not a "diplomatic game" but a "head-hunting game".
"I don't think this is a geographic rotation system," Lamy told the news agency in an interview on the sidelines of the semi-annual International Monetary Fund and World Bank meetings in Tokyo.
Formal nominations are not due until next month - but within the top ranks of international trade, names are already being assessed.
Apart from Groser there is Ghanaian former trade minister Alan Kyerematen, who was ordained by the African Union (AU) in July. Brazil's Ambassador to the WTO, Roberto Azevedo, has also been tipped.
The interesting point is why would anyone want to step into Lamy's shoes?
Trade liberalisation at a global level, as laid down in the Doha Round goals, has stalled.
Lamy said recently progress was possible and that he was "cautiously optimistic" now as opposed to "cautiously pessimistic" a year ago.
But he has said similar things before.
During Lamy's reign Russia acceded to the WTO (New Zealand played an early and pivotal role). But not a great deal of movement has taken place.
Whoever succeeds him will have to break a decade-old stasis on this front, possibly cope with a trade war between the US and China and deal with mounting protectionism.
Groser has some experience in herding the fractious cats at global level.
But being in charge of the WTO will test his powers to the nth degree. After the waters are tested at the EAS he, and the Government, will have a clear view of support.
Key thinks he is in with a chance.
"You wouldn't bet the ranch we would get him there - but he's a chance."
