In September 2014 a report by the Finnish corporate responsibility NGO Finnwatch investigated working conditions on IOI's estates in the southern region of Peninsular (West) Malaysia, in the states of Negeri Sembilan and Johor. Finnwatch conducted the research with the cooperation of the company, which facilitated access to its estates. The report found evidence of serious labour rights violations at IOI Group's plantations.

Examples of clear adverse human rights impacts caused by IOI Corporation, as evidenced by Finnwatch research, include:

1. Freedom from forced labour: IOI Corporation was found to keep possession of employees' personal documentation, including passports. Many of the workers stated that they were not able to get their passports even when they requested them. Confiscation or retention of passports is considered an indicator for forced labour by the International Labour Organization.

2. Right to freedom of association: The company was found to restrict employee access to trade unions, as well as restricting industrial action. The General Secretary of the National Union of Plantation Workers (NUPW), the only trade union in West Malaysia that represents workers in the plantation sector, reported that the union is denied access to foreign workers on IOI estates in order to provide training, to raise their awareness of their rights and organize them as union members. As workers do not have possession of their passports, they rarely leave the estates.

3. Right to an adequate standard of living: Some workers earned a salary that was below the statutory minimum wage, and were not compensated appropriately for overtime work. 

BankTrack wrote to 15 banks linked to IOI Corporation asking them how they had sought to prevent or mitigate these human rights impacts, and the results are presented in a February 2016 briefing paper.

IOI is a co-founder of the Roundtable on Sustainable Palm Oil (RSPO), although it has been suspended several times. It was partially suspended in April 2011, by being prevented from applying for new supply base certificates, due to specific concerns including disputes over native customary land leased by IOI for palm oil production in Sarawak (RSPO, April 2011).

In September 2015 IOI was again reprimanded by RSPO, and warned to address serious legal and policy non-compliances in Kalimantan, or face expulsion from the Certified Sustainable Palm Oil (CSPO) market (CRR, September 2015).

It was again suspended in March 2016 in 2016 for for clearing peatland areas and developing land without obtaining required permits. This led major buyers such as Unilever, Mars, Kellogg’s and Procter & Gamble to suspend their contracts with the company, affecting its income and share price (Aviva, 2018). It was re-admitted in August 2016 (in a move which Greenpeace described as being "let off the hook too easily"), although its customer Unilver only resumed sourcing from IOI in August 2017.

As owner of 30.4 percent of the Bumitama company, IOI also shares responsibility for that company’s illegal deforestation and peatland clearance in orangutan habitat on the PT LSM and PT GY plantations, as well as on the BSS plantation.

IOI has used its political weight within the industry to try to subvert progressive companies’ efforts to implement strong deforestation-free sourcing policies, and fought against efforts to establish traceability. However, IOI Loders Croklaan has recently started to engage with Forest Heroes and is developing a policy to address these issues.