In a last-ditch effort to purchase cheap shares, trader David Tweed has launched a legal bid to force diversified conglomerate Wesfarmers Ltd (ASX: WES) to open its register.

Before changes to the legislation could murder his business, Mr Tweed is reportedly back in Australia, mounting one last effort to buy shares for a fraction of their actual value, a practice for which he is notorious.

Mr Tweed's application, prepared by EC Legal, a firm associated with debt collection agency eCollect, alleges Wesfarmers breached the Corporations Act by neglecting to provide lists of members who hold fully paid and partially-protected ordinary shares.

A bill that would allow companies to block raiders to their share registers was introduced into Federal Parliament. Under the proposed legislation, access to the register would have to be for a ''proper purpose'', which would exclude making low-ball, off-market offers.The Australian Shareholders Association, however, has warned this might give companies too much power to refuse legitimate requests.

Although introduced earlier this year, the bill did not pass before the election was called. It may take another six months before the legislation passes both houses, according to reports.