More than three years after Germany's Love Parade disaster, which claimed 21 lives in a stampede during a music festival, prosecutors said this morning they had ended their investigation, paving the way for a trial.

In the 2010 tragedy, party-goers at the techno music festival were crushed to death as hundreds of thousands of young people tried to navigate the narrow tunnel that served as the only access to the grounds.

More than 500 people were injured.

Prosecutors said they had laid charges and would present details tomorrow of their case over the disaster in the western industrial city of Duisburg.

Media reports said charges would likely be laid against ten or 11 people.

The state had initially investigated 16 suspects, mostly city officials and staff of festival organisers Lopavent, amid claims that bad planning and poor crowd management were to blame for the deaths.

The then mayor of Duisburg, Adolf Sauerland, was forced to step down by a 2012 city referendum, accused of having ignored warnings that the venue was too small and the summer festival a disaster waiting to happen.

In the 24 July 2010 tragedy, a large crowd of revellers at one of Europe's top techno events was forced to go through a narrow tunnel that served as the only entrance and exit to the festival grounds.

An interim police report listed a catalogue of catastrophic mistakes in managing the crowd of hundreds of thousands of young people.

The grounds opened nearly two hours later than promised, leading to an initial blockage in the tunnel, and there were no loudspeakers to control the crowd, police said in the interim report.

Those killed, 13 women and eight men who were crushed, trampled to death or suffocated, included seven foreigners, from Australia, Italy, the Netherlands, China, Bosnia and Spain.