He is said to have transferred large sums of money overseas.

Mr Zhu said it would be easier to get Gao back than smuggling kingpin Lai Changxing because the fugitive banker had lied to Canadian authorities.

'The Canadian government will strip him of citizenship because he provided false information to them,' he said.

Mr Zhu was also optimistic about the eventual return of Lai, but admitted that there were still many difficulties to be overcome in that case.

'We have already promised not to execute Lai if he returns,' he said. 'He won't even face a suspended death penalty. Some have feared that he would be tortured if he was extradited back to China. I can promise that won't happen.'

Mr Zhu said Lai could learn from the example of his younger brother, Lai Changtu , who escaped to Australia but later surrendered to mainland authorities.

'Lai [Changtu] deserved the death penalty, but we treated him leniently. He was only sentenced to 15 years in prison and we just reduced that to 12 years. Lai Changxing could learn from his younger brother's example,' Mr Zhu said.

He said all the major hurdles for Lai to be deported back to China 'have been cleared', but admitted the chance for the kingpin's immediate return 'should not be overestimated'.

'This has become a very complicated issue. There are many factors to be considered,' he said.

China has extradition treaties with about 20 countries and Mr Zhu said they hoped to sign more such agreements.