Duncan, 35, has apparently filed for bankruptcy in London's High Court but has used his real name - Duncan Inglis - in the papers.
Earlier this year, Duncan and his fellow Blue stars - Antony Costa, Lee Ryan and Simon Webbe - appeared in ITV2 show The Big Reunion.
Blue, along with the other groups taking part, toured the UK in May and they are due to to join up with them again in December for a Christmas party tour.
The boy band, who rose to fame in 2001 with their debut single 'All Rise', are also embarking on their own tour next month.
During The Big Reunion, Duncan's bandmate Antony admitted that he had suffered money troubles after the group went their separate ways in 2005.
He said: "I thought Blue and the money were going to last forever and I totally lost control."
Duncan, who is dad to eight-year-old daughter Tianie-Finn, has not commented on the reports. Reveal has contacted his rep.