David Jackson, the chairman of infrastructure group Peterhouse, has told shareholders not to accept Babcock International's £95m offer for the company.
Jackson and fellow director Simon Foster said that the offer undervalued the group. Jackson and Foster had previously pursued a rival bid, which collapsed last month.
The rest of the Peterhouse board have recommended that shareholders accept the 64.8p a share offer.
Gordon Campbell, the chairman of Babcock, said: "For their own reasons, Jackson and Foster have declined to support this recommendation, but have been unable to provide an alternative offer."
Babcock shareholders agreed the board's decision to buy Peterhouse at an extraordinary general meeting this week. Babcock is awaiting acceptances from Peterhouse's shareholders.German contractor Hochtief has agreed to sell its 48% share in Dutch rival Ballast Nedam to TCN Property Projects and Wedge International Holdings. The two firms will each hold at 24% stake in the Dutch company.