Coleen had alleged that Vardy's Instagram account was the source of leaked stories about her in The Sun, a report in the Mirror said.
The women were at loggerheads in a public row following Wednesday's controversy.
Coleen, who has been married to Rooney since 2008, said she spent five months working it out and revealed that Rebekah had planted fake stories on her private Instagram account, the Mirror report said.
Rebekah denied the allegations and posted on Twitter: "As I have just said to you on the phone, I wish you had called me if you thought this.
"I never speak to anyone about you as various journalists who have asked me to over the years can vouch for.
"If you thought this was happening, you could have told me & I could have changed my passwords to see if it stopped.
"Over the years various people have had access to my insta & just this week I found I was following people I didn't know and have never followed myself.
"I'm not being funny, but I don't need the money, what would I gain from selling stories on you?
"I liked you a lot Coleen & I'm so upset that you have chosen to do this, especially when I'm heavily pregnant.
"I'm disgusted that I'm even having to deny this. You should have called me the first time this happened."
Rooney had previously said that she had removed access to all users except Rebekah to see her 'stories', and alleged a slew of "false" stories she posted there were on the tabloid.
( With inputs from IANS )