A court in The Hague on Tuesday said NN Group had not provided enough information about the costs of investment-linked insurance products sold in the 1990s and 2000s, scrapping an earlier ruling that had been favourable to the company.

NN said it would bring an appeal against the interim judgment to the Dutch Supreme Court, as it said the district court had misinterpreted "the law and societal views at the time the investment-linked products had been sold".

Although the interim judgement did not lead to an immediate obligation for NN to compensate customers, the company did say the case could ultimately have "substantial" financial consequences, which could not be reliably estimated at this time.

NN Group and other Dutch insurers have been dealing with issues related to these insurance policies, popularly known as "woekerpolissen" for years.

The common theme is that customers were not informed how much of their premiums went to actual investments, and how much went to cover insurers' costs.

Between 2008 and 2010 Dutch insurers collectively paid clients about 3 billion euros ($3.2 billion) in compensation over similar policies, but a number of consumer groups have since filed suits arguing the compensation was too low.

($1 = 0.9464 euros)

(Reporting by Bart Meijer, Editing by Louise Heavens)