The Financial Markets Authority is warning shareholders in some of the country's largest listed companies to be wary of unsolicited offers for their shares.
The authority says two companies, Share Buyers and Stock and Share Trading Company, have requested the share registers of 23 companies and plan to make offers to buy shares from shareholders.
Australia-based Stock and Share Trading Company has previously made unsolicited offers, including one for the failed finance company St Laurence.
The Authority is considering whether to require the two companies to include a copy of the authority's warning in a prominent position in their offer documents.
The regulator previously made a similar order against Christchurch-based Bernard Whimp, though it is not aware of any connection between Mr Whimp and Stock and Share and Share Buyers.
The Companies Office shows Share Buyers is registered to a Wellington address but its sole director is Ting Wei, based in Perth.
The two companies have requested the share registers of Abano Healthcare, AMP New Zealand Office, Argosy Property Trust, Cavalier Corporation, CDL Investments, Charlie's Group, DNZ Property Group, Fisher & Paykel Appliances, Fisher & Paykel Healthcare, Fletcher Building, Goodman Property Trust, Guinness Peat Group, Hellaby Holdings, Mainfreight, Michael Hill International, Nuplex, Skellerup, Telecom, Vector, The Bankers Investment Trust, New Zealand Refining Company, The Warehouse and TrustPower.