A method of forming a valve bag comprising the steps of: dispensing a first bag section (30; 130) and a second bag section (40, 140), each having an upper side (34, 44; 134, 144) and a lower side (36, 46; 136, 146); dispensing a combined and pre-sealed web of valve material, the combined and pre-sealed web of valve material being formed from a first and second web of valve material (1, 5), the valve material being plastic film, such that the combined and pre-sealed web of valve material is positioned between the first bag section (30; 130) and the second bag section (40; 140), wherein the combined and pre-sealed web of valve material has an upper side and a lower side and is formed of a plurality of valve strip portions each including at least one valve portion and at least one sealed portion, each valve portion being arranged to allow material to pass through the corresponding valve strip portion and each sealed portion being arranged to prevent material from passing through the corresponding valve strip portion; creating a combined web of valve bag material (50; 150), by contacting the upper side of the combined and pre-sealed web of valve material with the lower side (36; 136) of the first bag section (30; 130), and by contacting the lower side of the combined and pre-sealed web of valve material with the upper side (44; 144) of the second bag section (40; 140), the combined web of valve bag material (50; 150) being formed of a plurality of valve bag sections, each containing a valve strip portion; applying a sealing process (55, 155) to the combined web of valve bag material (50; 150), the sealing process defining each valve bag section; and separating adjacent valve bag sections into individual valve bags. dispensing a first bag section (30; 130) and a second bag section (40, 140), each having an upper side (34, 44; 134, 144) and a lower side (36, 46; 136, 146); dispensing a combined and pre-sealed web of valve material, the combined and pre-sealed web of valve material being formed from a first and second web of valve material (1, 5), the valve material being plastic film, such that the combined and pre-sealed web of valve material is positioned between the first bag section (30; 130) and the second bag section (40; 140), wherein the combined and pre-sealed web of valve material has an upper side and a lower side and is formed of a plurality of valve strip portions each including at least one valve portion and at least one sealed portion, each valve portion being arranged to allow material to pass through the corresponding valve strip portion and each sealed portion being arranged to prevent material from passing through the corresponding valve strip portion; creating a combined web of valve bag material (50; 150), by contacting the upper side of the combined and pre-sealed web of valve material with the lower side (36; 136) of the first bag section (30; 130), and by contacting the lower side of the combined and pre-sealed web of valve material with the upper side (44; 144) of the second bag section (40; 140), the combined web of valve bag material (50; 150) being formed of a plurality of valve bag sections, each containing a valve strip portion; applying a sealing process (55, 155) to the combined web of valve bag material (50; 150), the sealing process defining each valve bag section; and separating adjacent valve bag sections into individual valve bags.