The family of a Canadian schoolteacher say they're "completely stunned" after the Indonesian Supreme Court overturned the acquittal of Neil Bantleman and sentenced him to 11 years in prison.

Guy Bantleman, Neil's brother, said Thursday morning that heading into the verdict the family felt confident in the outcome.

"This came completely out of left field," Guy Bantleman told CTV's Canada AM from his home in Burlington, Ont.

Bantleman and Ferdinant Tijong were sentenced in April 2015 to 10 years in prison for sexually abusing three young children at a prestigious international school in Jakarta. They both maintained their innocence and filed appeals to the High Court, which acquitted them last August.

On Wednesday, the Supreme Court overturned the acquittal.

"The judge panel concluded that the defendants were proven to have violated the 2007 Child Protection Law," said Supreme Court spokesperson Suhadi, who uses a single name. "It did not only reinstate the District Court's verdict but also lengthened the sentence to 11 years."

The pair were also ordered to pay a $7,440 fine each or to serve six more months in jail.

Under Indonesian law, both Bantleman and Tijong still could challenge the sentence by filing for judicial review by the Supreme Court if they have new evidence.

Government 'deeply dismayed' by decision: Dion

Foreign Affairs Minister Stephane Dion said in a statement Thursday morning that the Canadian government is "deeply dismayed and shocked" by the Supreme Court's decision.

“This decision is unjust, given the many grave irregularities throughout the various proceedings in this case and the fact that all evidence presented by the defence has systematically been rejected. Mr. Bantleman and Mr. Tjiong were not provided the opportunity to demonstrate their innocence," Dion said. "Despite Canada’s repeated calls for due process, this case was not handled in a fair and transparent manner."

Dion said the outcome of the case has "serious implications" for Indonesia's reputation as a safe place for Canadians to work and travel.

He added that Canada would continue to raise Bantleman’s case at the highest levels while Canadian officials provide him with consular assistance.

Guy Bantleman said the family is meeting with Burlington MP Karina Gould on Thursday.

He said the "most daunting task" for Neil and his wife Tracy is dealing with reality of going back to prison.

"They're both tired, they both thought that we're very close to the end of this process and they'd be back in Canada in the coming weeks," Guy Bantleman told CTV News Channel on Thursday.

He said since the Liberal government was elected last year, the Bantleman family has received more support from Ottawa. He said Dion's statement on the matter was the "strongest" the government has made so far.

However, Guy Bantleman added that he wants to see Ottawa take action on his brother’s behalf.

"There need to be repercussions," he said. "It's blatantly obvious that this is about greed and corruption. There is no evidence whatsoever to support the allegations."

Guy Bantleman said Neil Bantleman was not in Jakarta at the time the ruling was handed down, and he will be working with consular officials to turn himself in.

Meanwhile, Tijong was taken from his house early in the day and is now serving his sentence at the Cipinang Prison in eastern Jakarta, according to an officials from the prosecutors' office.

Both Bantleman and Tijong worked at the Jakarta International School, which is now called the Jakarta Intercultural School.

The 2,400 students in the school include children of foreign diplomats and expatriates from about 60 countries along with Indonesia's elite.

The school's principal and a number of other teachers have said they believe Bantleman is innocent.

Last December, five janitors at the school who were arrested in the same case were sentenced to up to eight years in jail. Police said a sixth suspect in that group committed suicide.

With files from The Canadian Press and The Associated Press