The offer is well below the latest market price of RON3.2 a share.
Interagro, which is controlled by Romanian businessman Ioan Niculae, is offering RON1.4 million for the 7.45% stake in Giurgiu Nav.
The offer will take place between August 1 and August 22. Swiss Capital is bookrunner on the deal.
Giurgiu Nav reported a loss of RON1.2 million in 2012, narrower from RON6.7 million a year earlier, on total sales of roughly RON35 million. (EUR1=RON4.3886)