Swiss national Xavier Andre Justo has appealed against the three-year prison term handed down by the Bangkok South Criminal Court on Aug 17 for blackmailing his former employer PetroSaudi International.

His new lawyer Worrasit Piriyawiboon filed the appeal in the court this morning with 59 pages of supporting documents, just two days before the period to appeal expired.

Among the reasons for the appeal was that Justo did not tamper with the documents he obtained from PetroSaudi International and that it was his first offence.

Worrasit said any damage to the image of Malaysian Prime Minister Datuk Seri Najib Tun Razak was because of the activities of third parties who doctored or tampered with the documents that they received from Justo.

He said Justo did not tamper the documents.

"They who doctored the information have to take responsibility and face legal action," Worrasit told Bernama after filing the appeal here today.

Worrasit said in his opinion, Justo's role in the case was not serious as the documents were tampered by other people.

He said it was also the first time Justo committed an offence, and so he should not have to get to undergo the heavy punishment given, and instead could have a lighter sentence.

"It should be a six months or one year-jail term, or suspended sentence or just a fine," Worasit said.

Worrasit said while the normal appeal period is 30 days, Justo was given an extra 30 days as to give time for him (Worrasit) as the new lawyer, to prepare the documents for the appeal.

Previously, Justo's legal team was led by Pranot Kalanuson.

As for how Justo was doing at the moment, Worasit said his client had adapted himself to the current environment.

"I visit him every week, already about 4-5 times now. Justo said he is fine. He has many friends and they understood him as he is a likeable man," said Worasit.

Justo was sentenced three years jail on Aug 17 after pleading guilty to blackmailing his former employer PetroSaudi International.

He was arrested at his house on Samui Island in the southern province of Surat Thani on June 22 after officials from PetroSaudi filed a complaint that Justo attempted to blackmail the company for 2.5 million Swiss francs with documents stolen from the company.