Speaking on The Wales Report education debate, Mr Lewis - who is not seeking re-election on 5 May - said Labour would heed Prof Sir Ian Diamond's review.
The Welsh Government currently pays up to £5,190 towards tuition fees for Welsh students in the UK.
Opposing parties argue it is not sustainable.
Mr Lewis rejected this, saying: "Obviously it is, I have budgeted this for this year and next".
Students from Wales pay £3,810 towards their tuition fees, wherever they study in the UK.
Speaking for the Conservatives, Angela Burns said her party would introduce a system to pay half of Welsh students' rent, wherever they study in the UK.
For Plaid Cymru, Simon Thomas said his party would give all Welsh students loans but if they decided to live in Wales, then they would not have to pay the money back.
Welsh Liberal Democrat Eluned Parrott said they would scrap the current system of university tuition fee subsidies and introduce a system to help meet up-front living costs.
UKIP's Susan Boucher said it would replace the tuition fee grant with loans for Welsh students studying in England, however, fees would end for Welsh students who study science, technology, engineering, mathematics and medicine subjects in Wales.
Welsh Labour will "honour" a student finance review due in the autumn, Education Minister Huw Lewis has said.