As part of his visit to the world's second largest economy, the Prime Minister met the Chinese Premier for what he said was a "warm and engaging" discussion.
Although Key got no assurance that China would renegotiate, he said he would not expect to get one at this point.
"I didn't expect to come here today and for them to say, 'Yes, we're definitely doing it'," he said.
"In terms of a formal renegotiation of the FTA ... I think that's possible but there's more work to be done."
Key said he specifically raised Australia's more favourable access to Chinese dairy markets with the Premier.
"[China's] argument is that of course dairy's not that significant to Australia - their main focus actually is minerals into China and to some degree, meat," Key said.
"That may well be the case but they've still got on the face of it what looks like better access than us."
New Zealand and China were making good progress on some areas outside the FTA such as meat access, he said.