* Sales sum undisclosed
* Analyst sees deal value $117 mln-$143 mln
* Aker BP plans further Valhall, Hod stake reduction (Adds company's spokesman, analyst, oil ministry)
OSLO, Dec 4 (Reuters) - Norwegian oil firm Aker BP said on Monday it had agreed to sell 10 percent stakes in two North Sea fields to private equity-backed Pandion Energy for an undisclosed amount to help pay for expansion plans in the area.
The deal will leave Aker BP with 90 percent stakes in both the Valhall and Hod fields, and will help pay for projects such as the Valhall Flank West, estimated to come on stream in 2020.
A previously announced intention to reduce Aker BP's stake to around 67 percent was unchanged, a company spokesman said.
Brokerage Sparebank 1 Markets said the deal could be worth some $117 million-$143 million, but the company declined to comment on the amount.
"We would expect at least one more Vallhall/Hod deal to be announced in the short term," Sparebank 1 Markets said in a note to clients.
Aker BP in October announced a $2 billion deal to buy Hess Corp's 64.05 percent stake in the Valhall field and 62.5 percent in Hod, raising its ownership to 100 percent, but added it would seek a partner for the licences.
"After we announced the Hess transaction, we have seen strong interest to partner with Aker BP in the Valhall area. Through this transaction, we get a partner that shares our ambition of developing the upside potential in these fields," Aker BP Chief Executive Karl Johnny Hersvik said in a statement.
Pandion in June won permission from Norway's energy ministry to hold oil and gas licences, and is backed by private equity fund manager Kerogen Capital.
Aker BP's top owners are Norwegian investment firm Aker ASA with a 40 percent stake and BP Plc with 30 percent.
The original Hess transaction and the Pandion deal are both subject to customary approvals by regulators, which Aker BP said it expected to receive by the end of 2017.
Norway has a policy of requiring more than one partner in each licence to safeguard and promote checks and balances, although there is no specific limit on the maximum allowed ownership, an energy ministry spokesman said. (Reporting by Terje Solsvik and Nerijus Adomaitis, editing by David Evans)