Helsinki - A kiss-and-tell book about Finnish Prime Minister Matti Vanhanen and the related issue of how much privacy leading politicians can claim may feature in a new trial, reports said Wednesday.

The prosecutor as well as the author and publisher of the book have filed appeals to the Supreme Court. A decision on a possible hearing is expected in four months, Finnish news agency STT reported.

An appeal court in February said the book violated Vanhanen's privacy and ordered publisher Kari Ojala and author Susan Ruusunen, whom Vanhanen once dated, to pay fines based on the book earnings.

Ruusunen's book Paaministerin morsian (The Prime Minister's Bride) was published in 2007 after the relationship had ended. The two - both divorced - met via an internet dating site in 2006.

Last month, Vanhanen announced his engagement to Sirkka Mertala. The couple have been dating for a year.

In a related development, a new survey published Wednesday suggested Vanhanen's approval ratings have dropped to their lowest level since he became prime minister almost six years ago.

Only 32 per cent of the 943 voters polled early April said they were satisfied with Vanhanen's leadership, according to the survey commissioned by the newspaper Kaleva.

The controversy over the Ruusunen book was one factor that hit Vanhanen's ratings, but the economic downturn was the main factor. The government's overall ratings were also hit by the financial crisis, the survey said. (dpa)