The couple, who tied the knot in July 2010 and are parents to 18-month-old son Flynn, were said by an apparent close friend to be "in trouble".
"She's not wearing her ring, and she's had a lot on her plate," the source told Australia's Famous Magazine.
"It could be that somewhere along the way her relationship with Orlando may have slipped between the cracks."
However, Kerr's manager has since dismissed the suggestions, claiming: "There is absolutely no truth in the headline or story".
The couple are believed to have begun dating in 2007.
Photo gallery - Celebrity break-ups during 2012:
Copyright: Twitter Myleene Klass