TAOISEACH Brian Cowen told the Dáil he was "removing ridiculous distinctions" between Government departments to make Ministers of State "more effective".
Mr Cowen said he wanted the Ministers to have "a wider remit to cover all the policy aspects that may reside in different departments".
He also wanted "effective cross-cutting responsibility" across departments, which "is something of a culture change in public administration".
Following the announcement of the Minister of State portfolios, the Taoiseach said he had made it "very clear to everyone in Government that I do not believe in territoriality or Ministers having functions that are not substantive".
The Government was "trying to introduce innovative, more progressive ways to ensure Ministers of State are given an opportunity to show the full range of their talents by having access to various departmental areas, in particular areas of activity".
The Taoiseach added that "all members of the Government have been given an onerous task which they will seek to perform conscientiously and on the basis of an esprit de corps in the Government that insists on everybody being respected and getting their job done in a co-operative and collegiate manner".
"That is the way good government operates, and I intend to ensure it occurs."
He was responding to Labour deputy leader Joan Burton, who questioned having "multiple Ministers of State in one department".
"What will the five Ministers of State at the Department of Education and Science do when they sit down together?" she asked.
Ms Burton called on the Taoiseach to publish "formal, dedicated orders for the duties, budget and powers of Ministers of State".
She said that without these a Minister, "even one who serves in four different departments, is a poor creature".
The Dublin West TD congratulated Minister of State Martin Mansergh who had been appointed to the Office of Public Works (OPW) and to the Department of Arts, Sport and Tourism, but said the latter department "struggles to occupy the time of one full Minister".
However, the Taoiseach said that Mr Mansergh and Minister Martin Cullen "will ensure the State properly promotes, acknowledges and represents the cultural life of the nation, and will do all they can to assist creative flair in all the arts".
He said Mr Mansergh had a "particular interest and expertise in this area" and will do this very well.
"Joining up arts and his responsibilities in respect of the heritage function of the OPW is entirely logical and complementary, and fits his talents admirably."
He cited the area of children as having "cross-cutting responsibilities", including education, health and justice.
"This approach is proving correct. Similar approaches are being taken in the areas of elderly people and integration," Mr Cowen added.
The Taoiseach thanked "everybody for the courtesy shown to me in the good discussions I had with all the Ministers of State, both outgoing and incoming, on the role they can play in working with Ministers to ensure their work is valuable and fulfilling for them professionally, adds value to the Government's work and is well managed and presented".
"This is a genuine sentiment and a hope I have for all those who have been privileged to have been asked to serve, including last week.
"We intend to do this to the very best of our ability."
