Premier Investment's lawyers have sent a letter to Myer demanding it to release quarterly trading figures or legal action will be taken.
The letter said that withholding such information could be unlawful.
Legal firm Arnold Block Leibler's partner Jeremy Leibler issued a letter to the department store that said withholding the information contravenes with the Corporations Act.
“Our client is extremely concerned about the implications of this decision.
“In particular, it appears that this policy change was made in bad faith for the improper purpose of depriving shareholders of important information while the company's leadership and performance are being questioned.
“The timing of the decision supports this position.”
Premier plan to use the company's AGM on November 30 to seek a second strike vote against the remuneration report.