Dr Brady has kept a relatively low profile since new allegations emerged of the handling of child abuse concerns raised about notorious paedophile cleric Fr Brendan Smyth.
With just weeks to go to the 50th Eucharistic Congress, Archbishop Martin said the challenges facing the church were not about just one person.
"Cardinal Brady has said that he is staying and that he has lots of support from people; I've never commented and I don't know any thing of those details," he said.
Asked if he supported Cardinal Brady, Dr Martin replied: "I've made no comments on other bishops."
Earlier this month, Dr Martin said it would not be "appropriate" to comment on the Cardinal's position.
The beleaguered leader of the Catholic Church in Ireland has faced calls to consider his position after the broadcasting of a BBC documentary focusing on Smyth.
It revealed how, in the mid-1970s, the then Fr Brady and two other priests had been given crucial information by 14-year-old abuse victim Brendan Boland concerning Smyth, but church authorities did not pass it on to parents of other victims of Smyth.
Archbishop Martin has called for an independent international inquiry into the crimes of Smyth to be carried out.
Dr Brady, who has publicly apologised to Mr Boland, had claimed he received a lot of support from within the church to stay on in his role.