As fashion giant Burberry plans to shut its South Wales factory, church leaders have joined the petition.
More than 300 workers face losing their jobs if the Treorchy site closes at the end of March.
Rhondda MP Chris Bryant wrote to the Church Commissioners asking them to intervene, as he believes the Church of England holds about £2.5m worth of shares in the company.
In a letter, Mr Bryant compares the crisis with the Church's action over the British Airways worker suspended for wearing a cross.
He writes: "Jesus was particularly harsh in his criticism of poor and miserly employers. I very much hope the Church Commissioners will use their shareholder power to exert an influence on Burberry either to change its mind or at least to be as generous as possible to the workers and the community.
"I hope you will agree with me that an ethical investment must mean an investment in a company that values both its workers and the community in which it is based.
"When the Church threatened to remove its investments in British Airways over one employee's treatment, the company backed down.'
Chairman of the Church's ethical investment advisory group, John Reynolds, replied saying they had written to Burberry's bosses over their proposals.
