The Saints currently find themselves in third place in the Aviva Premiership table after some impressive results in recent weeks, even with a host of their stars away on international duty at the ongoing Six Nations tournament.
With second place Saracens losing to Worcester on Friday night, Northampton will be looking to close down the nine-point gap on the London outfit when they travel to the Madejski Stadium.
The Exiles sit in eighth place in the Premiership table having had an inconsistent campaign so far both domestically and in Europe, having been knocked out of the Heineken Cup.
However Mallinder is fully aware of the threat Irish pose and believes his side are in for a tough afternoon on Sunday.
He told Eurosport: "London Irish have a good home record this season, and with some powerful runners out wide like Jonathan Joseph and Sailosi Tagicakibau we will have to be alert defensively.
"They are very organised and in Tom Homer they have one of the best goal-kickers in Aviva Premiership rugby.
"But the spirit in training has been good this week and we are feeling positive ahead of the trip to Reading."