Luxembourg offered on Monday to chip in financing to close an ageing French nuclear power plant near its border, saying the tiny nation could be obliterated if the station malfunctioned.

During a press conference with his French counterpart Manuel Valls, Luxembourg's Prime Minister Xavier Bettel said a problem at the Cattenom plant could "wipe the duchy off the map".

"The Cattenom site scares us, there's no point in hiding it," he said of the plant that has been in operation since the mid-1980s. "Our greatest wish is that Cattenom close."

Luxembourg "would be prepared to make a financial commitment to a project, which would have to be cross-border... at Cattenom that is not nuclear in nature."

Valls -- who was on a one-day visit to the nation of about 500,000 -- said France has pledged to cut its reliance on nuclear energy from more than 75 percent to 50 percent by shutting 24 reactors by 2025.

"Message received," he added.

France has several ageing nuclear power plants that are unsettling its neighbours. Germany demanded last month Paris shutter its oldest station, Fessenheim, which sits near the German and Swiss borders.

Fessenheim houses two 900-megawatt reactors and has been running since 1977. Due to its age activists have long called for it to be permanently closed.

French President Francois Hollande has pledged to shut down the Fessenheim plant by the end of his five-year term in 2017.