Acute necrotising pancreatitis is the most serious form of acute pancreatitis and accounts for the majority of complications. Treatment of patients with pancreatic necrosis is still controversial. There is a well-established definition for acute pancreatitis and consequent pancreatic fluid collections. However, it has been identified a group of patients who represent a separate entity and whose collections may prompt additional change from the definition of acute pancreatitis. Imaging investigations in these patients have well defined subacute collections that evolve from severe acute necrotising pancreatitis involving greater than 30% of the gland. Although these collections are not completely liquefied, they do not meet criteria for pseudocysts, however, at the same time, they are morphologically different from acute pancreatic necrosis seen during initial presentation of acute pancreatitis. It has been used to call "subacute" these collections of necrotic pancreatic tissue or "subacute pancreatic necrosis". The purpose of this review is to summarise the subacute collections of necrotic pancreatic tissue and its complications, discussing treatment options of the complex pancreatic and peripancreatic collections found in these patients, focusing on the management of subacute pancreatic necrosis.