The All Blacks thumped Australia 37-20 in Yokohama on Saturday to complete a 3-0 Bledisloe Cup whitewash, but Hansen warned that players will continue to risk injury unless they get enough rest.
"They don't get enough of a break," he said on Sunday.
"You can't keep going round and round and round without running out of petrol -- at some stage you've got to recharge the tank."
New Zealand face 2019 World Cup hosts Japan in Tokyo next weekend before completing their five-match tour against England, Ireland and Italy.