Grant Holt scored his 19th goal of the season to set the ball rolling and Wes Hoolahan quickly doubled the home side's advantage to effectively wrap up the points before half-time.
Oldham were on the back foot for virtually the entire 90 minutes and did well to limit the damage to just two goals as an impressive Norwich side turned on the style.
The incessant pressure finally told in the 21st minute when Chris Martin's cross from the right was nodded home at the back post by Holt.
Norwich then doubled their advantage just after the half-hour mark, a swift break down the left involving Martin and Adam Drury culminating in Hoolahan blasting the ball home from just outside the box via a slight deflection off the head of Sean Gregan.
Norwich had numerous chances to increase their advantage after the break, but Oldham defended well and finally created a few openings of their own in the closing stages, with Fraser Forster producing one excellent fingertip save to keep out Danny Whitaker's header.