The boy band's third album Midnight Memories is set to topple Swing Both Ways from the number one spot after selling 145,000 copies in its first three days of sale.
According to The Official Charts Company, Midnight Memories is currently out-selling every other artist in the top five combined.
Gary Barlow's Since I Saw You Last is in second place and Williams' Swing Both ways is in third.
Should the band's album continue to sell at its current pace, Daft Punk's Random Access Memories could be in danger of losing its 'fastest-selling album of 2013' title.
The French duo's fourth album sold 165,000 copies in its first week of sale when it was released in May earlier this year.
One Direction have made multiple TV appearances to promote their new album in the past weeks.
Performances at the MTV American Music Awards, Children In Need, and most recently The X Factor, have helped propel the group towards their second number one.
Right Place Right Time by Olly Murs has climbed 92 places to fourth place following the release of his new single "Hand On My Heart", and Boyzone's twenty year anniversary album BZ20 is at number five.
Susan Boyle's Home For Christmas has debuted mid-week at number seven.
In the mid-week singles chart, "Under Control" by Calvin Harris, Alesso and Hurts looks set to knock Lily Allen's "Somewhere Only We Know" off the number one spot on Sunday.