HMNZS Hinau was one of three composite New Zealand-built Castle-class trawlers commissioned by the Royal New Zealand Navy during World War II.

The vessel was ordered after the New Zealand government, facing a requirement for more minesweepers to operate in home waters, chose the Castle-class design because it was simple enough to be built with the country's limited ship construction facilities at the time.

[1] Hinau was laid down in 1940 and was of a composite design, using Kauri wood due to a shortage of steel at the time.

[4][5] It was noted that the steering gear was stiff, needing 2 men for manoeuvring, and her boiler room was full of problems, with the report stating at the end “It is apparent that “HINAU” will not be able to operate effectively as a L.L.

[9][11] In 1958, the hulk of Hinau would be towed and ran aground for use as a breakwater and shingle bin in Whakatīwai, where she remains today.