"The questions is how as a country and how do our companies respond?"
Mr Key said there had been no impact on demand as a result of the Fonterra botch-up, in fact demand had been growing.
Last week's visit to the country had also been very positive, he said.
"By any measure, the Chinese government has absolutely rolled out the red carpet for us, and in fact, in their country, that is of huge importance and symbolism."
Mr Key denied New Zealand was in danger of putting to much emphasis on China, putting the country at risk from a collapse in that market.
"It just doesn't make sense to turn your back on that opportunity.
"But I think what is really important for the government is to have a plan that is much broader than just China, and we do that."
Mr Key was also visiting Hong Kong, which he said represented only a fraction of the sales of China, but "we're still here because we're still focusing on this market, as we will when we visit other European markets."
Mr Key also told Q+A his visit had not been overshadowed by gaffes from senior government ministers Judith Collins and Hekia Parata.
"I don't believe so. There are always domestic issues I have to deal with along the way," he said.
He said there were lessons to be learned and that the ministers would reflect and be more careful in future.