* Transocean, advisers had been acquitted of all charges
* Norway appeals parts of the decision
By Ole Petter Skonnord and Gwladys Fouche
OSLO, July 16 (Reuters) - Norway is appealing a decision by an Oslo court to acquit Swiss-based rig firm Transocean and some of its advisers of tax fraud in connection with shifting assets between affiliated companies, the police economic crimes investigation unit said.
On July 2 the Oslo district court acquitted several Transocean subsidiaries and three individual advisers of all charges.
It also dismissed the prosecution's demand for 1.8 billion crowns ($290.7 million) in damages. Instead it asked the Norwegian state to pay the defendants' costs, which were 41 million crowns.
The National Authority for Investigation and Prosecution of Economic and Environmental Crime said on Wednesday the state would appeal the acquittal of Transocean Inc and Transocean Deepwater Drilling Company, as well as the acquittal of two of the three advisers.
"This is very important to us. This is a question of principles," Morten Eriksen, the prosecutor in the case, told Reuters.
"If the verdict stands, then tax law and tax treaties would be so undermined that higher authorities must examine the question."
Transocean could not immediately be reached for comment.
The company was accused of having underpaid taxes in 2000-2002, when it acquired three rivals worth $27 billion and moved its headquarters to Switzerland from the Cayman Islands.
The prosecution claimed that the underpayments stemmed from several transactions in connection with the sale of 12 oil rigs from Transocean's Norwegian subsidiary to other company divisions.
Transocean was also accused of several instances of providing tax authorities with incomplete or misleading information.
The Norwegian police unit that investigates economic crime launched an investigation into the transactions in 2005. (editing by Jane Baird)