The Mirror reported that the actor, who plays Kat Slater in the long-running soap, will be “temporarily written out” of forthcoming plots.
A “well-placed insider” told the publication that Wallace, 48, was called to a “crisis meeting” with producers, during which her behaviour was “called into question”.
“Scriptwriters are currently coming up with a storyline to explain Kat’s temporary exit from Walford,” the source claimed.
A BBC spokesperson said: “We don’t comment on artist’s contracts.”
The Independent has contacted Wallace’s agent for comment.
The report comes ahead of the 35th anniversary celebrations for the soap, with a number of major stories promised for several special episodes.
Jon Sen, executive producer of EastEnders said: “For the 35th anniversary we wanted to entertain the EastEnders audience on the iconic river which has heralded the start of the show for 35 years.
“This unmissable week of episodes is destined to be exciting, gripping and heart-breaking – it will be a week that will go down in EastEnders history.”