The 29-year-old is one of the original members of pop trio Sugababes and more recently of girl group MKS.
She is the latest star to be declared bankrupt by a court after being chased for an unpaid tax bill earlier this month.
Buena's comeback project, MKS, was launched last year with her original Sugababes band members, Siobhan Donaghy, Keisha Buchanan.
But their first single, Flatline, as a reunited trio didn't enter the top 50 in the Official Singles Chart.
They haven't released any music since.
It's thought Buena boosts her income with PR appearances and modelling.
Sugababes formed in 1998 with founding members Siobhan Donaghy, Mutya Buena and Keisha Buchanan.
Their debut album, One Touch, achieved moderate success peaking at number 26 in April 2001.
Donaghy left the group after rumours of a rift with Buchanan and the group were dropped by their record label.
With the introduction of Heidi Range, the group began to experience more commercial success.
They released three studio albums before Buena announced her departure in December 2005, leading to Amelle Berrabah being brought in to replace her.
Mutya Buena is the latest in a line of pop stars who have struggled financially.
Blue band members Duncan James, Simon Webbe, Antony Costa have all filed for bankruptcy as have Westlife singer Shane Filan, S Club 7 singers Jo O'Meara and Paul Cattermole and Fazer from N-Dubz.
Kerry Katona from Atomic Kitten has been declared bankrupt twice.
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Mutya Buena has been declared bankrupt by a High Court judge.