The German forces facing the British were very strong. "Field Marshall List had three corps, including armored, infantry, and mountain divisions". To the east of the Pindus mountain range, there were six Greek divisions in poor shape. There were also the Australian and New Zealand Divisions in the ANZAC Corps.
By 16 April, the British forces were seen to be vulnerable to attack from the east. They had assumed that they could hold the Olympus Passes long enough to withdraw the ANZAC Corps. It now seemed a possibility that the Germans could move quickly south to Thessaly so fast as to reduce the possibility that the British forces could move to Larisa.The New Zealand 21st Battalion "at the Platamon tunnel" reported seeing 150 German tanks and that they were pressing an attack.
The Germans sent motorcycle troops against the 21st Battalion, which mauled the motorcyclists. At the evening of 15 April, a unit of German armor came up to the vicinity of the 21st Battalion.
The battalion was attacked from the direction of the coast and from the inland direction. The battalion was able to hold out against the attacks they had faced so far.
The German attacking force was strengthened during the night of 15 to 16 April. By dawn on 16 April, the leftmost company of the 21st Battalion was attacked by infantry. By 9am, they were attacked by the tanks "along the coast". This is based on the account in "Greece, Crete, and Syria" by Gavin Long.