Junior explorer Poseidon Nickel has found that 40 of its share issues over the past few years were done without a legally required cleansing notice.

A cleansing notice must be issued by a company following the placement of new shares to allow the shares to trade without restrictions.

Poseidon (ASX:POS) requested a trading halt in March after it realised several of its past share issues did not comply with the Corporations Act.

The company said at the time it had received no complaints about the matter, but that it intended to rectify the error.

While undertaking its review of past share issues, Poseidon also found that an offer of shares to an employee had not been made in accordance with Class Order 03/184.

The Class Order provides conditional relief from disclosure and licensing provisions of the Corporations Act for certain offers involving shares made to full time or part time employees under an employee share scheme.

Poseidon now has to seek validating orders for all of the non-compliant share issues from the Federal Court and has been told the matter will be heard on June 13.