Multiplex has served a second legal action for £38m, this time against Dorman Long Engineering, the parent company of its former steelwork contractor, Cleveland Bridge UK.
Multiplex accuses Dorman Long Engineering of breaching a parent company guarantee made in September 2002.
The writ, issued last month at the Technology and Construction Court, claims Dorman Long Engineering agreed to guarantee due performance of the contract by its subsidiary.
Multiplex claims that Cleveland Bridge breached the subcontract, leading to substantial loss and damage that its parent failed to cover.
Cleveland Bridge is counter-claiming that Multiplex tried to rive it into bankruptcy under an "armageddon plan".
This writ is separate to Multiplex's action against Cleveland Bridge, but a spokesperson for steel firm said it would be dealt with at the same trial. Multiplex declined to comment. The case is due to be heard on 25 April.