Murphy has not featured for Rovers since suffering a hamstring strain in the 1-1 derby draw against Burnley at the start of the month.
Dunn was an unused sub for that game and the 2-0 defeat to Blackpool last time out but last appeared in October's 1-0 win over Sheffield Wednesday, where he laid on Grant Hanley's winner before suffering a calf injury.
Both men were pushing for inclusion against Brighton on Saturday and the torrential downpour that rendered the Ewood Park playing surface unplayable has given them extra time to reach full fitness.
Full-back Markus Olsson is available once more after being struck down by illness ahead of the Blackpool game, where Jake Kean was a surprise inclusion in place of Paul Robinson in goal.
Mauro Formica (foot) remains a doubt, while fellow winger Fabio Nunes and veteran striker Nuno Gomes (both hamstring) are sidelined.
Blackburn were top of the table when they lost their first game of the season to Boro at Ewood in September.
Steve Kean resigned as manager a week later and the pre-season promotion favourites have won just three times in 15 subsequent matches, including a solitary victory in nine since Berg's appointment.