Singer Whitney Houston has been forced to postpone the first date of her European tour due to illness.

Her representative said in a statement that Houston had an upper respiratory infection and doctors had ordered her to postpone Tuesday's opener in Paris.

The tour will now kick off in Manchester on Thursday, while the Paris date will be rescheduled. Some fans who saw the 46-year-old perform in Australia expressed disappointment with Houston's vocals. There were suggestions that the singer was unable to hit the high notes at a show in Brisbane in February, although some fans defended her.

Houston released her first album, 'I Look At You', for seven years in 2009, featuring collaborations with Alicia Keys and R Kelly. The singer, whose hits in the 1980s and 1990s included 'I Will Always Love You' and 'I Wanna Dance With Somebody', battled drug problems for many years. She has had several stints in rehabilitation clinics but says she is now drug-free.

The Grammy award-winner divorced singer Bobby Brown in 2007, after 14 years of marriage. Houston has custody of the couple's teenage daughter.