Tourist Visa to Zambia from Hong Kong (passport holder of HONG KONG SAR)

Dear Sir/Madam,

My boss and his wife are planning to visit Zambia as tourists
during May 29-30, 2015 in Livingstone, Zambia, they are holding Hong Kong SAR passport, do they need to apply a tourist type to Zambia?

Please advise. If yes, please advise where we can apply for them asap.

Thanks & Best Regards,
Rose Wong
HONG KONG