* Cinven's Viridium also interested in portfolios - sources
* Cinven willing to inject further capital into Viridium - sources
* High regulatory hurdles likely - sources (Adds further details)
By Alexander Hübner and Arno Schuetze
MUNICH/FRANKFURT, Oct 30 (Reuters) - Britain's Resolution Group, Swiss Re and private equity firm Cinven have expressed an interest in acquiring two large German life insurance portfolios owned by Ergo and Generali, sources familiar with the matter said on Monday.
Munich Re's primary insurance affiliate Ergo and the German subsidiary of Italy's Generali are considering the sale of their respective portfolios of 6 million and 4 million policies in run-off.
A spokeswoman for Ergo said the company had yet to decide whether to sell the portfolio but would do so soon.
Swiss Re and Cinven declined to comment, while Resolution was not immediately available to comment.
Cinven has indicated that it is willing to inject money into its life insurance and pensions group Viridium - owned by Cinven and Hannover Re - to acquire the German portfolios.
Ergo and fellow insurers are struggling to pay guaranteed returns to clients because of record-low interest rates. Combined with more stringent European capital rules, these have prompted some to offload some life insurance operations.
Financial services groups specialising in the run-off of life insurance policies are vying for these portfolios. They acquire policies until their expiry and aim to turn a profit by measures such as cutting administrative costs.
Ergo's run-off life portfolio has assets of 56 billion euros ($65 billion), while Generali's is around 40 billion euros.
The sales of the Ergo and the Generali portfolios would mark the largest ever sale of closed books. Dutch insurer Aegon sold a 9 billion pounds ($12 billion) book of closed UK life business last year and Britain's Standard Life has said it is open to the sale of its 16 billion-pound closed annuity portfolio.
In Germany, only a handful of smaller portfolios of the roughly 90 life insurers have changed hands, including those of Arag Leben, Delta Lloyd, Basler Leben, Heidelberger Leben and Skandia. Cinven bought Heidelberger Leben and Skandia Leben, which are now rebranded as Viridium.
The German financial watchdog will have to approve any sale, which would depend on the solvency of the future owner.
"The hurdle will continue to be very high," said a person in the industry. "It is unlikely that anything will happen quickly." ($1 = 0.8607 euros) ($1 = 0.7591 pounds) (Additional reporting by Paul Arnold in Zürich and Simon Jessop in London; Writing by Tom Sims; Editing by Ludwig Burger, Greg Mahlich)