Here you are, Section 8 of the Ordinance states as follows:
PART III
SALARIES TAX
(Amended 36 of 1955 s. 10)
(1) Salaries tax shall, subject to the provisions of this Ordinance, be charged for each year of assessment on every person in respect of his income arising in or derived from Hong Kong from the following sources-
(a) any office or employment of profit; and
(b) any pension.
(1A) For the purposes of this Part, income arising in or derived from Hong Kong from any employment-
(a) includes, without in any way limiting the meaning of the expression and subject to paragraph (b), all income derived from services rendered in Hong Kong including leave pay attributable to such services; (Amended 69 of 1987 s. 2)
(b) excludes income derived from services rendered by a person who-
(i) is not employed by the Government or as master or member of the crew of a ship or as commander or member of the crew of an aircraft; and
(ii) renders outside Hong Kong all the services in connection with his employment; and (Added 2 of 1971 s. 5. Amended 69 of 1987 s. 2)
(c) excludes income derived by a person from services rendered by him in any territory outside Hong Kong where-
(i) by the laws of the territory where the services are rendered, the income is chargeable to tax of substantially the same nature as salaries tax under this Ordinance; and
(ii) the Commissioner is satisfied that that person has, by deduction or otherwise, paid tax of that nature in that territory in respect of the income. (Added 69 of 1987 s. 2)
(1B) In determining whether or not all services are rendered outside Hong Kong for the purposes of subsection (1A) no account shall be taken of services rendered in Hong Kong during visits not exceeding a total of 60 days in the basis period for the year of assessment. (Added 2 of 1971 s. 5)
Recently, I handle a case wherein the Sale Director contracted with an oversea company registered in HK under Part XI of the Companies Ordinance but anticipated to stay in HK for less than 60 days is applying to Inland Revenue Department for full exemption from HK Salaries Tax under Section 8 Part III 1(B).