Germany, shaken by a neo-Nazi murder wave, was weighing Tuesday whether to outlaw a far-right party, a decade after a first attempt failed because undercover agents had infiltrated its top ranks.

Politicians are divided on whether to seek a ban of the National Democratic Party of Germany, known by its acronym NPD, fearing that another judicial stumble would only strengthen the group.

The NDP, which was founded in 1964 and calls itself a "patriotic force," has been labeled racist, anti-Semitic and revisionist and is widely considered close to violent neo-Nazi groups.

The interior ministers of Germany's 16 states were set to meet Wednesday in the eastern city of Rostock to make a decision, to be followed by a vote of state premiers on Thursday.

A former senior member of the party had links to the so-called National Socialist Underground terror cell whose members murdered at least nine Turkish and Greek men and a policewoman between 2000 and 2007.

Chancellor Angela Merkel's conservative government has voiced doubts about legal action, fearing the NPD could challenge a ban by Germany's top court before the European Court of Human Rights.

To ban the NPD, the government must prove that the party, even if it doesn't openly advocate violence, threatens democracy with an "actively aggressive, combative" attitude against the state.

The 2003 case against the NPD crumbled after it was discovered that paid state informants and secret service undercover agents had infiltrated the top ranks of the party.

The court threw out the case because it could not determine to what degree the agents had influenced the party's actions. The state meanwhile was unwilling to divulge the identities of its agents.

Legal expert Guenter Frankenberg, who worked on the previous case against the NPD, voiced doubt on whether indeed none of the evidence against the party could be sourced to state informants.

He said the court would set a very high legal bar for banning a political party and warned of the risk that another failed attempt to ban it would lend the party a veneer of legitimacy.

The consequences could be far-reaching, Frankenberg told dpa: "If the NPD terrorizes those who think differently, the police may just say in future that what the party is doing is legal."

Germany's federal and state government has collated a roughly 1,000 page dossier against the NPD, with 2,649 documents, including speeches, press releases and other publications.

They insist that informants are no longer active, and that the material is not colored by these agents - although a crucial question will be whether the evidence is indeed all cleared.

While most of Germany's states have backed the new attempt to ban the party, the federal government has remained non-committal, weighing the risk of another failed case against the NPD.

The NPD has assembly seats in two eastern states, which means it qualifies for official party funding, although it has failed to pass the 5 percent hurdle to enter the national parliament.