Senator Aquilino "Koko" Pimentel III said employers will be violating labor laws should they compel their employees to get vaccinated against COVID-19 before returning for work.
Pimentel maintained on Friday that "COVID-19 vaccination is not mandatory" and people who opt out or are yet to be inoculated should not be discriminated upon.
"Vaccine-related discrimination is not to be allowed or tolerated under the law. Employers will be violating labor laws if they do that," said the senator, who is also a lawyer.
"Any act or policy which makes it mandatory or appear to be mandatory is therefore discriminatory and should be challenged," he added.
Pimentel earlier objected to the use of the word "passport" to call the certification to be issued to vaccinees.
The term, he said, connoted mobility and might become a requirement for non-essential and international travels, and entry into business establishments.
He said this would result in the discrimination of those who refuse to be vaccinated.
The Senate, in passing the COVID-19 Vaccination Law, later renamed the certification to "vaccine cards" instead.
On Thursday, March 4, Labor Secretary Silvestre Bello III said it is illegal for employers to enforce the so-called "no vaccine, no work" policy.
Employers who would impose such rule will be sanctioned administratively, the labor chief said.