The death of The Cranberries lead singer Dolores O'Riordan is not being treated as suspicious, British police say.

O'Riordan was found dead at a London hotel on Monday morning (local time) and officers initially described the death as "unexplained" but now say nothing suspicious had been found.

The case is being passed to a coroner to determine the cause of death.

The 46-year-old Irish singer was in London to record vocals for a cover of The Cranberries hit Zombie by Los Angeles rock band Bad Wolves.
Dan Waite of music label Eleven Seven said O'Riordan left him a voice message earlier on Monday saying she was looking forward to the recording.

"She sounded full of life, was joking and excited to see me and my wife this week," he said.

"The news of her passing is devastating and my thoughts are with Don, her ex-husband, her children, and her mother."

Irish Prime Minister Leo Varadkar said that "for anyone who grew up in Ireland in the 1990s, Dolores O'Riordan was the voice of a generation."

In her hometown of Limerick, residents signed a book of condolence at the city council offices. Mayor Stephen Keary said O'Riordan "put Limerick on the music map and on a world stage."

"She achieved so much in her short years. Her memory will live on," he said.

O'Riordan struggled at times with fame after the spectacular success of The Cranberries' 1993 debut album Everybody Else Is Doing It, So Why Can't We? cutting short a tour in 1996 citing exhaustion and disillusionment.

She left the band in 2003 and recorded two solo albums, before The Cranberries reformed in 2009.

In 2015 O'Riordan pleaded guilty to headbutting and spitting at an Irish police officer following an alleged incident on a plane.

Medical records given to the court indicated she was mentally ill at the time of the altercation.

After her court hearing O'Riordan urged other people suffering mental illness to seek help.

The Cranberries' 1990s hits included Dream, Linger and Zombie.