The transport ministry will demand the resignation of all board members of companies affiliated with four public expressway corporations who assumed their posts after retiring from the public firms, transport minister Chikage Ogi said Thursday.

They all should step down before the corporations hold shareholders' meetings later this year, Ogi told a news conference.

The move is part of ongoing efforts to privatize all four of the heavily indebted expressway corporations, which are funded and supported by the government in accordance with proposals submitted to Prime Minister Junichiro Koizumi by a key government panel in December.