Amy Winehouse's record label, Island, have voiced concern about the singer's new material, it's been reported.
The demo tracks, written during Winehouse's holiday in the Caribbean, are believed to be heavily inspired by reggae.
A number of the tracks contain “very dark” lyrics which focus on her relationship with estranged husband Blake Fielder-Civil, a source told The Sun newspaper.
“Amy was very productive during her stay in St Lucia,” the unnamed source said.
"She wrote a hell of a lot of songs, but the majority of them just aren’t hitting the mark.
“She seems to have ditched her trademark vintage soul sound and is now heavily influenced by reggae.
“Her bosses don’t think it’s a wise move to change her style so sharply and have told her that."
Winehouse, one of Island Records' leading artists, is expected to record her follow-up to 2006's 'Back To Black' this year.
The singer spent three months in the Caribbean over the new year.
Since returning to the UK last month, she has pleaded not guilty to a charge of assault.
Amy Winehouse in the Caribbean