'Lazaretto' was a US unrealised plan for a landing at Gasmata, on the southern coast of New Britain island just to the west of Thilenius Harbour (late 1943).
The plan was cancelled in favour of the 'Director' (i) seizure of Cape Merkus of the Arawe peninsula of New Britain.
A grass airstrip had been built at Gasmata to service a nearby plantation, and this had also been used occasionally by the Royal Australian Air Force as a staging field. Elements of a Japanese special naval landing force occupied the area on 8/9 February 1942, and Japanese engineers soon lengthened the runway to 3,200 ft (975 m). No significant Japanese air group was ever based there, however.
The headquarters of General Douglas MacArthur’s South-West Pacific Area command planned to seize Gasmata as a preliminary to the 'Backhander' landing on Cape Gloucester, but eventually replaced it with the assault on Arawe. Australian forces reoccupied the area on 28 March 1944, and found that the airfield had been abandoned by the Japanese some time well before this.