A trek following a 273-kilometre trail traversing Slovenia by which over a hundred Allied prisoners of war were led to freedom 80 years ago will pay tribute to the most successful POW escape of World War II.

The commemorative trail, named The Crow's Flight, runs from Ožbalt near Maribor in the northeast where the POWs were maintaining a railway line for the Nazi Germany, to Otok near Metlika in the south from where they were flown to Italy's Bari.

They managed to break free with the help of the locals, the Slovenian Partisans and British intelligence.

The Raid at Ožbalt liberated around 90 prisoners, originally held in a Nazi camp in Maribor's Melje district, who were repairing the railway line near Ožbalt.

On 31 August 1944, with the help of a Partisan unit and locals, they escaped to the densely wooded hilly area of Pohorje, where they were joined by other Allied prisoners of war.

The group of over 100 people travelled through the Upper Savinja Valley, the Menina Plateau, and across the Sava River, arriving in Semič on 10 September 1944. On 17 September 1944, they were flown from the Partisan airfield in Otok to the Allied base in Bari.

Australian POW Ralph Churches described this operation in his 1996 book A Hundred Miles as the Crow Flies, which inspired the creation of the 273-kilometre memorial trail.

A signpost for the International Memorial Trail of Alliance The Crow's Flight. Photo: Andreja Seršen Dobaj/STA

The path will be covered in two stages, the first scheduled from 31 August, the anniversary of the operation, until 5 September and featuring several members of the Slovenian Armed Forces (SAF).

The second from 24 September onwards will see SAF members joined by service members from the nations of the liberated POWs: Australia, New Zealand, the UK and the US.

According to the Association of Slovenian Officers, the march aims to maintain the tradition of friendship and mutual support with allied countries.

The idea is to make the hike a recurring event, Major General Dobran Božič, the association's president, told reporters in Maribor on 28 August.

Service members are expected to be joined by other hikers as well as school children on the trail.

The anniversary will also be commemorated at the International Research Centre for the Second World War Maribor, established in the former Stalag XVIII D camp in Melje, where the prisoners were kept.

New memorial plaques will be unveiled at the centre on 6 September and a conference held that is also expected to be attended by descendants of the POWs involved in the operation.