Senior diplomat Carl Worker, who recently ended a posting to China, is standing in for him.
Mr Moore, 66, said he had not contemplated what he would be doing once he returns to New Zealand.
"I certainly want to do some writing and catch up on that. But anything could happen. For a couple of months, I want to go to sleep, go to the beach, then plot my way back."
Mr Moore is a former director-general of the World Trade Organisation and has been close to the progress of the Trans Pacific Partnership.
Until his stroke in April, he was leading NZ's effort in Washington to try to get Congress to approve Trade Promotion Authority for the TPP.
That was passed, allowing President Barack Obama to present any agreement from next week's final TPP talks in Maui, Hawaii, as is, for a yes or no vote without amendment.
"It could fall over," Mr Moore said. "We just don't know ... it could go ahead or it could come and have another go later."