Mahathir made the statement after meeting Bosnian Prime Minister Adnan Terzic in Sarajevo on Tuesday.
The former Malaysian prime minister, who now works as an advisor for big corporations including the Petronas oil company, is on a visit to Bosnia-Herzegovina, during which he has met the highest state officials, including members of the state presidency.
The construction of the 330-kilometre highway is only one of the projects in which Malaysian investors may be interested.
Design documentation for the highway is expected to be completed by spring 2006, when the Bosnian government will decide whether construction works will be financed by awarding a concession for the highway or by seeking loans.