The invention relates to a package for a fluid material, the package (8) comprising a bag of flexible sheet material (2), where the package (8) comprises two opposite side walls (12, 14) and a bottom (22) which bottom (22) before filling of material presents two fields (18, 20) received between the side walls (12, 14), and where further the bottom (22) and the side walls (12, 14) are tightly sealed with each other along the side edges (3, 5) of the package (8), where a creased section (13, 15) is arranged along the transition edges (50, 52) between the bottom (22) of the package (8) and its respective side walls (12, 14) for forming of a series of to each other connected lamellae (54, 56; 58, 60) whereby the side walls (12, 14) are kept substantially vertical and substantially perpendicular to the bottom (22) along the transition edges (50, 52) when the package (8) is filled with the fluid material (9) wherein the package (8) is stabilised against tipping over. The invention further relates to a method of producing a stabilised package (8).