* Appoints external investigators
* Will check if corruption, money laundering involved
* PM Reinfeldt urges strong ethical codes (Adds PM comment, share price reaction)
STOCKHOLM, Oct 3 Nordic telecoms firm TeliaSonera said on Wednesday it had appointed lawyers to investigate allegations of wrongdoing related to its purchase of a 3G licence in Uzbekistan in 2007.
Prime Minister Fredrik Reinfeldt welcomed the move, which comes days after Swedish prosecutors launched a preliminary investigation into the high-profile 2.3 billion crown ($348 million) deal.
He said it was time for the company - more than one third owned by the state - to clear up all the questions surrounding allegations of corruption.
The most recent accusations, aired in a Swedish TV programme, are that Telia bought its Uzbek 3G licence from a firm reported to have close ties with the daughter of Uzbek president Islam Karimov.
Karimov has ruled his gas-rich republic since independence from the former Soviet Union two decades ago.
Telia, which has denied any wrongdoing, has appointed law firm Mannheimer Swartling to look at whether its purchase of the licence "involved any form of corruption or money laundering," the company said.
The company also said it had appointed Sweden's former ambassador to Russia, Tomas Bertelman, as a strategic advisor on matters related to the company's operations in Central Asia.
The Swedish state and other shareholders sharply rebuked Telia earlier this year for allowing authorities in Azerbaijan, Belarus and Uzbekistan to access its networks to keep tabs on anti-government activists.
Reinfeldt said companies operating in countries like Uzbekistan, regularly accused of abusing human rights, should have strong ethical codes.
"But I don't think that we should limit their ability to do business for the simple reason that trade and business are a way to open up countries that are very closed," he said.
"Clearly, though, there is more need to be careful when there is such a great lack of transparency."
Telia shares closed down 0.5 percent at 47.09 crowns, underperforming a flat DJ Stoxx 600 European Telecoms index .
Telia CEO Lars Nyberg has staked his job on the company being exonerated.
"The allegations directed at TeliaSonera are very serious and therefore it is important that an independent party now reviews the transaction and truly gets to the bottom of all allegations and rumours which have flourished in recent weeks," Nyberg said in the company statement.
Russian telecoms operator MTS has run into trouble in Uzbekistan, having had its Uzbek licence withdrawn and assets confiscated. ($1 = 6.6036 Swedish crowns) (Reporting by Simon Johnson; Editing by David Cowell)