China transit Visa for 8 hours at airport

Hi There, myself and four friends are currently in Hanoi, Vietnam.

On Saturday 28th October we are flying from Hanoi to China (Guangzhou airport) and then Guangzhou toAuckland, New Zealand. We have an 8hours at airport.

Do we need a Chinese Visa for this? If so how do we apply?

We are New Zealand Citizens & Residents.

Thanks you, Charlotte