CARS WITH DRIVERS CHINA
Car Rentals in Hong Kong and China are generally not available as 'self-drives' for Westerners
Hong Kong Airport has super public transport links, car hire options are limited for non-residents.
Hiring a Chauffer Driven Car Rental in China is often the best option for business or tourist travellers, English speaking drivers act as guides as well as drivers.

Cheap Car Hire in Hong Kong

As a general rule most non-residents will find it very cumbersome to rent a car in Hong Kong or China. Here at PriceCarHire.com we offer cars for hire with drivers in China. However we don't offer self-drive rentals in  Hong Kong or China, and at the moment we don't offer Chauffer Driven Rentals in Hong Kong, but if you are using a Chinese Car Rental with a Driver, there is no issue with them driving you to Hong Kong (City or Airport).

Self-Drive Car Hire in Hong Kong and China

Self-Drive Car Rentals in China are generally only for 'locals' or 'ex-pats'.

Quick searches of guidebooks and forums will immediately advise all 'westerners' not to even dream of driving in China - especially in the cities. If you wish to drive in China yourself, you will have to get a permit, which isn't straightforward:

Applying for a Chinese Driving License : International Driving Permits

Firstly, you need to find a local Public Security Bureau (PSB) office. The following documents must be presented at the PSB:
Passport (& copy of the passport main page, copy of the valid Chinese visa, copy of the latest entry stamp in your passport)
Residency permit valid for at least 3 months
International Driving License
A medical examination certificate
A copy of both sides of overseas driving license
  Digital color photo with white background
  Your Chinese name.
  Height
  Deposit:2000RMB (Approx US$290 or €229)

In addition there is a written examination: A multiple choice test of 100 questions and it takes 15-20 working days!

Whilst there are somewhat lesser driving permit restrictions for Drivers from Hong Kong, Mainland China and Macau entering each others countries, it's still most likely easier to get a taxi, use public transport or use a chauffeur driven car unless you are staying for a long time.