In January Kallakis and co-conspirator Alexander Williams were found guilty and sentenced to seven and five years respectively after they defrauded two banks out of £740m.
Kallakis posed as a Mayfair property tycoon and used the funds to sustain a lavish lifestyle which saw him own a private jet, a helicopter and a fleet of luxury cars.
Solicitor General Oliver Heald referred the case to the Court of Appeal and pushed for longer sentences for the pair.
In a statement Heald said: “We welcome the Court’s finding that ‘the culpability of the offenders was at the highest level because they set out and persisted over a significant period with planning, determination and audacious dishonesty to commit a commercial fraud with international proportion.
"We are pleased that the court agreed that consecutive sentences were required to reflect the fact that two separate banks fell victim to the offenders."
Between 2005 and 2008 the pair created an elaborate and fraudulent network of business arrangements through which they borrowed huge amounts of money to buy a commercial property empire and fund lavish lifestyles.
The bulk of the loans were secured from Allied Irish Banks although Bank of Scotland also lost a significant amount after agreeing to a loan the men said was to convert a passenger ferry into a luxury yacht.
The banks risk controls and background checks during a property binge was also criticised during earlier court proceedings.
