Former TV One newsreader Richard Long may face legal action over his Hanover Finance advertisements.
Financial Markets Authority chief executive Sean Hughes said, "It is under consideration".
Long, who fronted One News between 1988 and 2003, promoted Hanover Finance, which in 2008 froze repayments to investors owed $554 million.
His voiceover ads ran several times each night late in 2007 saying, "This One Weather update is brought to you by Hanover, a New Zealand business with the size and strength to withstand any conditions."
The FMA intends to file a civil case in the New Year against some former directors and promoters of Hanover Finance over statements in its December 2007 prospectus.
Mr Hughes told the Herald that Long's advertisements might not be deemed to be promoting a prospectus.
"But I don't want to draw any conclusions on that until we've had legal advice."
Long could not be reached for comment last night, but he has expressed his regret about his role as the television voice for Hanover.
He has also said it would be unfair to hold celebrities responsible for endorsements, as it was unlikely they would ever have known how sound the firm was.
The FMA's main targets are former directors and promoters of the Hanover group.
Hanover Finance former director Mark Hotchin's New Zealand assets are already subject to a court-ordered freeze.
Mr Hughes said the FMA was also considering action against Eric Watson, another high-profile businessman associated with Hanover Finance.
In June 2008 - one month before Hanover Finance collapsed - the Advertising Standards Authority upheld a complaint by a financial adviser, who said Long's scripted statement was "grossly misleading".
Former Commerce Minister Simon Power introduced draft legislation in August which would impose fines of up to $1 million for individuals and $5 million for companies for misleading statements in product disclosure statements and advertisements.