Smith, up for her role in Mrs Biggs, and Duff, recognised for the second series of Accused, will go up against fellow Accused star Olivia Colman.
Call The Midwife, Line of Duty and Sherlock - all made for the BBC - will vie for best drama series.
Coronation Street, EastEnders and Hollyoaks will compete for best soap.
Sean Bean, best known for portraying Boromir in The Lord of the Rings film trilogy, has also been nominated for best actor for his role in Accused - Jimmy McGovern's Emmy-winning anthology drama series.
However despite receiving three nods in the acting categories, the show - in which each episode follows a different character as they await their verdict in court - failed to pick up a nomination in the drama category.
Also nominated for best actor are Lennie James for his role in police drama Line of Duty and Oliver Lansley for Best Possible Taste: The Kenny Everett Story.
Jack Whitehall is nominated for best comedy performance for Channel 4's award-winning comedy drama, Fresh Meat, along with Jessica Hynes for Twenty Twelve and Ruth Jones for Stella.
Fresh Meat is also up for best scripted comedy along with Alan Partridge: Welcome to the Places of my Life and Twenty Twelve.
In the entertainment category, Britain's Got Talent will compete against Keith Lemon's panel game show, Celebrity Juice, and magic show Dynamo: Magician Impossible.
Meanwhile, the best entertainment performance will be a battle between Ant and Dec in I'm A Celebrity...Get Me Out Of Here!, will.i.am for The Voice and Charlie Brooker for 10 O'Clock Live.
Clare Balding has been nominated for best presenter for her role in the BBC's coverage of the Olympics, which has also been nominated for best live event. Also in the running in that category is the London Paralympics on Channel 4 and the Queen's Diamond Jubilee Concert on BBC One.
In the international category, Girls, written by and starring Lena Dunham will compete against the acclaimed terrorism thriller Homeland and Danish political drama, Borgen.
The awards, which will also honour history, arts, science and children's programming, will be presented at a London ceremony hosted by comedian Jo Brand on 19 March.
The nominations for all 25 awards can be found on the RTS website.
Sheridan Smith and Anne Marie Duff have both been nominated for best actress at this year's Royal Television Society (RTS) Programme Awards.