ZURICH (Reuters) -The Swiss Attorney General's Office has handed a former wealth manager at Pictet Bank a six-month suspended prison sentence and fined the private bank for money laundering in a Petrobras-related probe, the government said on Tuesday.

Pictet was ordered to pay 2 million Swiss francs ($2.5 million) for failing to take all reasonable and necessary measures to prevent transfers from the account of a Brazilian public official aimed at concealing their criminal origin, the Swiss government said in a statement.

Swiss prosecutors have been working for years to identify assets and bring forward prosecutions in relation to a sprawling international corruption case linked to Brazilian state-run oil company Petrobras.

"We confirm that this matter, which involves several financial institutions, has been resolved for Pictet," Pictet said in a statement.

"It represents neither an admission of guilt nor an acceptance of liability on the part of Pictet and is not related to its asset management, asset servicing or alternative assets entities," the private bank added.

The payments were made between June 2010 and May 2013 from an account held in the name of an offshore firm whose beneficial owner was a Petrobras employee, the Swiss government said.

The former Pictet manager approved transfers of assets that originated from corrupt payments for the operation of oil rigs and totaled more than $4.1 million, the government added.

He was found guilty of aggravated money laundering the government alleged was made possible by organisational shortcomings at Pictet.

Brazil's so-called Car Wash probe, known in Portuguese as Lava Jato, began in 2014 with the arrest of a currency dealer and mushroomed into the country's biggest ever graft scandal, in which hundreds of executives, officials and politicians have been convicted.

($1 = 0.8126 Swiss francs)

(Reporting by Ariane Luthi;Editing by Dave Graham and Emelia Sithole-Matarise)