NME.com reported the songs dated back to Lorde's High School band in 2011/12.
On Facebook, the seven-piece band describes its sound as "future noir" and lists its influences as Dimmer, Bloc Party, Massive Attack and The Mars Volta.
Since going solo, Lorde has gone on to win international acclaim - including two Grammy Awards - thanks to her No. 1 hit Royals and album Pure Heroine.