Medical reasons for early retirement

Hi , is it possible to get letters from doctors to certify that the patient is suffering from a rare disease to support early retirement. Please advise

Taken from the labour department web site - http://www.labour.gov.hk/eng/faq/cap57l_whole.htm
Under what circumstances should an employer pay his employee long service payment?
A5.
An employee employed under a a continuous contract for not less than 5 years is eligible for long service payment if:

　( 1 ) he is dismissed (except by reasons of redundancy or summary dismissal due to the employee’s serious misconduct);
　( 2 ) his fixed term employment contract expires without being renewed;
　( 3 ) he dies during employment;
　( 4 ) he has been issued a certificate in a specified form by a registered medical practitioner or a registered Chinese medicine practitioner, certifying that he is permanently unfit for his present job and he resigns; or
　( 5 ) he is aged 65 or above and resigns on ground of old age.
Hope this helps.

Thanks for the website but if I opt for early retirement due to illness, and obtain a medical certificate will
The employer accepts and will I be entitled to the company’s benefits for normal retirement? Also is it common for doctors to issue such letter

The minimum requirement is that you have worked for the same company for no less than 5 completed years.
The thing is your employer isn't obliged to pay you if you just decide to resign unless you provide them the following:
"
he has been issued a "certificate in a specified form by a registered medical practitioner or a registered Chinese medicine practitioner,"certifying that he is permanently unfit for his present job and he resigns;

If you can provide the above kind of certification your employer is obliged to pay you your long term benefits by law, call up the labour department & have a chat with them.

I think if you can prove any illness that directly effects you in your job, a doctor will issue you that type of certification.