The company said its sustainability committee would take on the commission's role to review a labour practice assessment.
The world's largest sustainable palm oil producer established the commission in March after the United States imposed a ban on imports from the firm over accusations of forced labour used in production.
The commission comprised the ethical trade consultancy Impactt and three labour rights experts. The commission's role was to review Impactt's assessment of the firm's labour practices and its proposed remedies.
One commission expert resigned in March and was replaced. But the new appointee, rights lawyer Justine Nolan, and another expert, migrant rights activist Andy Hall, quit on Wednesday, citing concerns about a lack of transparency and delays in conducting the assessment.
Responding to the resignations, the company said Impactt had not been able to complete its assessment because of pandemic-related restrictions that hindered travel inside Malaysia and limited face-to-face interviews and fieldwork.
"As the assessment is incomplete, SDP has been unable to engage with the commission as anticipated," the company said, adding that Hall would still work with SDP to improve foreign worker recruitment processes.
SDP Group Managing Director Mohamad Helmy Othman Basha said in the statement: "We are moving forward, working with Impactt and key stakeholders to protect the rights of workers and keep them safe."
(Reporting by Mei Mei Chu; Editing by Edmund Blair)