Education Minister Ruairi Quinn said the Cabinet has not discussed reintroducing third-level fees but warned he had not ruled anything out.
The senior Labour minister, who signed a pledge before the election against student charges, said he had not come under any pressure from Government colleagues over a return to fees.
"The matter hasn't been discussed. There is a resource issue clearly, just on the sheer numbers. The whole question of finance is going to have to be addressed but there are no proposals at the present being considered," Mr Quinn said.
The minister said the Government would have to look at ways to finance the growing demand in the education sector. But he added: "I have not ruled anything in or anything out."
Mr Quinn signed a Union of Students in Ireland (USI) pledge during the election campaign that Labour would not reintroduce third-level fees in government, or support an increase in the Student Services Charge.
But the minister said the Government had to accept Budget 2011, which will see the registration fee increase from 1,500 euro to 2,000 euro.
"It's what I said at the time and it's what I intend to try and do but I recognise that I have limited room for manoeuvre than perhaps I thought I did have," the minister said.
In a speech on the future of the third-level system at the Royal Irish Academy in central Dublin, Mr Quinn warned of a huge growth in demand in education over the next two decades, which he claimed was projected conservatively at 72%.
He said 20 new post-primary schools would be needed over the next five years totalling around half a billion euro.
Mr Quinn also reiterated his concerns about the current points system associated with the Leaving Certificate, claiming it should be examined in line with the review of the second-level curriculum.