Rihanna has risked sparking more controversy after she was snapped puffing a suspicious-looking roll-up cigarette on holiday in Hawaii - and then boasting about what it contained on Twitter.com.

The Umbrella hitmaker is currently taking a break in the Pacific paradise, and she was photographed on Sunday relaxing on a sun lounger as she smoked a brown, tapered cigarette.

The pictures emerged after the singer made two references to cannabis on her Twitter.com page, and the images have provoked further controversy following recent scandals over her racy promos, her hit track S&M and the expletive pendant she wore around her neck during a visit to a church in Brazil last year.

On Thursday, Rihanna tweeted, "4:20... Hi", referencing a time long associated with cannabis culture after Californian teenagers in the 1970s would meet after school at 4.20pm to smoke dope.

On Sunday afternoon, she took to her Twitter account again to write, "Kush rolled, glass full... I prefer the better things!" Kush is a strain of cannabis popular in the U.S.

Hours later, pictures emerged of the singer barefoot and smoking her roll-up as she soaked up the sun.

Last year, her hit track S&M was banned in 11 countries and her raunchy behaviour in the promo for her chart-topping single We Found Love provoked a storm of criticism.