Do i need to get my luggage and declare at costums during 21h layover in Guangzhou?

Hello, I want to fly from Osaka to Auckland on China Southern. Can I bring the duty free allowances for New Zealand (3 litres of spirits and 6 bottles of wine) from japan if I carry it in my checked laguage? Or would I have to go throu costoms when I have a day layover and visit the city/stay in a hotel?