Swedfund has previously been criticised for investing in companies that contribute to "land grabbing", where large amounts of land in developing countries are bought up by foreign companies.
Swedish National Radio now reports that many of the 38 companies Swedfund owns shares in admit to neglecting human rights and social issues in regards to how they treat their workers.
Swedfund's CEO Anders Craft admits that these companies need to improve on a number of issues, including the working conditions of their employees.
"I think this applies to environmental issues above all, as well as not firing pregnant women and making sure that wages are decent and correspond to the person's skills", he tells Swedish Radio News Ekot.
The investigations carried out by Swedfund itself show that six of their companies pay their workers salaries well below the minimum wage.
Anders Craft says that Swedfund will not sell its shares in the companies, but will rather help them work on improving these issues.