The present invention relates to a method for forming a package by moulding a cardboard blank in such a manner that a margin area (2) of the blank, surrounding a middle portion (1) of the blank, is bent upwards to form side walls of the package while the middle portion forms a bottom of the package. The cardboard blank prior to moulding is provided with at least one area (4) of reduced bending stiffness being located in a transition zone (3) between the side walls and the bottom. The package is moulded from the blank so that the at least one area (4) of reduced bending stiffness is located in the bended areas between the side walls and the bottom and extend in the running direction of the bend. The invention further relates to a package and a package blank that can be used for forming said package.