The pair have reportedly been contacted to perform on the BBC One talent show's semi-final on May 26 and the final on June 2.
The move is said to be a decision by producers in order to improve the show's ratings, after it was beaten by Britain's Got Talent at the weekend.
A BBC insider told The Sun: "If the show keeps bleeding two million viewers a week, serious changes are needed at the highest levels and no-one is safe.
"It's the first year of the show and clearly it needs some tweaking."
Coaches Jessie J, Danny O'Donoghue, will.i.am and Sir Tom Jones have also reportedly been told to "toughen up" in future shows.
Cheryl Cole recently said that she finds it hard to watch The Voice UK due to the talent of the singers.