Whitney Houston, who ruled as pop music's queen until her majestic voice was ravaged by drug use and her regal image was ruined by erratic behaviour and a tumultuous marriage to singer Bobby Brown, has died. She was 48.

Beverly Hills police Lieutenant Mark Rosen told reporters outside the Beverly Hilton that Houston was pronounced dead at 3.55pm on Saturday (12.55pm on Sunday, New Zealand time) in her room on the fourth floor of the hotel. Her body remained there and Beverly Hills detectives were investigating.

"There were no obvious signs of any criminal intent," Rosen said.

Houston's publicist, Kristen Foster, said the cause of death was unknown.

Rosen said police received an emergency call from hotel security about Houston at 3.43pm. Paramedics who were already at the hotel because of a Grammy party unsuccessfully tried to resuscitate the singer, he said.

Houston's end came on the eve of music's biggest night - the Grammy Awards. It's a showcase where she once reigned, and her death was sure to cast a heavy pall on tomorrow's ceremony.

Her longtime mentor Clive Davis was to hold his annual concert and dinner today at the same hotel where her body was found, and a representative of the show said it would proceed.

Producer Jimmy Jam, who had worked with Houston, said he anticipated the evening would become a tribute to her, and he expected there to be one at the Grammys as well.

Houston was supposed to appear at the gala, and Davis had told The Associated Press that she would perhaps perform: "It's her favourite night of the year ... (so) who knows by the end of the evening," he said.

Houston had been at rehearsals for the show earlier in the week, coaching singers Brandy and Monica, according to a person who was at the event but was not authorised to speak publicly about it. The person said Houston looked dishevelled, was sweating profusely and liquor and cigarettes could be smelled on her breath.

Two days ago, she performed at a pre-Grammy party with singer Kelly Price. Singer Kenny Lattimore hosted the event, and said Houston sang the gospel classic Jesus Loves Me with Price, her voice registering softly, not with the same power it had at its height.

Lattimore said Houston was gregarious and was in a good mood, surrounded by friends and family, including daughter Bobbi Kristina.

"She just seemed like she was having a great night that night," said Lattimore, who said he was in shock over her death.

Aretha Franklin, her godmother, also said she was stunned.

"I just can't talk about it now," Franklin said in a short statement. "It's so stunning and unbelievable. I couldn't believe what I was reading coming across the TV screen."

Recording Academy President and CEO Neil Portnow said Houston "was one of the world's greatest pop singers of all time who leaves behind a robust musical soundtrack spanning the past three decades."

"Her powerful voice graced many memorable and award-winning songs," Portnow said. "A light has been dimmed in our music community today, and we extend our deepest condolences to her family, friends, fans and all who have been touched by her beautiful voice."

At her peak, Houston was the golden girl of the music industry. From the middle 1980s to the late 1990s, she was one of the world's best-selling artists. She wowed audiences with effortless, powerful, and peerless vocals that were rooted in the black church but made palatable to the masses with a pop sheen.

Her success carried her beyond music to movies, where she starred in hits like The Bodyguard and Waiting to Exhale.