After the creation of the Commonwealth of Australia in 1901, Norfolk Island was placed under the authority of the new Commonwealth government to be administered as an external territory. During World War II, the island became a key airbase and refuelling depot between Australia and New Zealand, and New Zealand and the Solomon Islands. The airstrip was constructed by Australian, New Zealand and United States servicemen during 1942. Since Norfolk Island fell within New Zealand's area of responsibility it was garrisoned by a New Zealand Army unit known as N Force at a large Army camp which had the capacity to house a 1,500 strong force. N Force relieved a company of the Second Australian Imperial Force. The island proved too remote to come under attack during the war and N Force left the island in February 1944.
What minor event did Norfolk Island become an important airbase and refueling station during?