The 39-year-old took to Twitter to deny reports that her husband Stephen Belafonte, also 39, is to be investigated by police over the imprisonment allegations.
She wrote: "Pls don't belive what you read it's all lies lies lies as usual [sic]"
A rep for Mel added: "Both Mel and Stephen categorically deny this is true and the police have not contacted Stephen."
According to The Sun, police are investigating a case of false imprisonment that was reported on 15 December.
The Metropolitan Police said: "We can confirm police in Kensington and Chelsea borough are investigating an allegation of false imprisonment. The allegation was reported on Monday 15 December. We are not prepared to discuss further."
Spice Girl Mel was hospitalised on December 11, meaning she missed the first part of The X Factor final. The Sun alleged Mel was held hostage in her London home the day before.
When Mel returned to The X Factor on 14 December, fans were quick to comment on her appearance and the fact she wasn't wearing her wedding ring.
This is not the first time Mel has had to publicly defend her marriage. Both she and Stephen have absolutely denied the violence claims against him.
At Christmas, Mel shared a family snap of them with their daughter Madison, three, and Phoenix Chi, 15, and seven-year-old Angel, Mel's daughters from previous relationships.