THE government is considering appointing another junior minister to the Department of Finance to provide back-up to finance minister Brian Lenihan as he undergoes treatment for cancer in the coming months.

However, the possibility of a senior cabinet minister filling in on occasions when Lenihan is unavailable is also being "kicked around", and may end up being the favoured outcome.

Although he will have to undergo intensive treatment for cancer, Lenihan has made it clear that he does not see himself as a "part-time minister" and that he would be "fulfilling the essential functions of my office". However, there will inevitably be times in the first half of the year when he will unavailable because of the treatment.

The monthly Eurogroup meeting of eurozone finance ministers is an obvious example. While the Ecofin meetings can be handled by Department of Finance officials, Eurogroup gatherings require a minister to be present. The idea of moving an existing junior minister across to the Department of Finance has been considered, with the highly regarded existing ministers of state, Dara Calleary and Billy Kelleher, being seen as the most likely choices.

Barry Andrews is also seen as a candidate because he has the advantage of sitting at cabinet in his capacity as minister for children.

However, there is a view in some quarters of government that a junior minister filling in might send out the wrong signal internationally. The possibility of other cabinet ministers being asked to fill in occasionally is now looking more likely, senior sources say.

Defence minister Willie O'Dea, who is tipped for an economic portfolio in any cabinet reshuffle later in the year and who has a background in accountancy, and justice minister Dermot Ahern are seen as the two most obvious candidates to substitute for Lenihan.

"Willie would be an obvious one. He is very competent with regard to finance. He knows his stuff and he has done this kind of thing in the past," one senior figure said.

There is continued speculation about a cabinet reshuffle but, having come through such a turbulent period in the months leading up to Christmas, Taoiseach Brian Cowen is unlikely to introduce any changes until the autumn.

One option being considered is the creation of a new Department of Infrastructure, which would merge the Department of Transport with elements of ­Environment.