The battle of Moremonui (, or , ) was fought between NgÃÂti WhÃÂtua and NgÃÂpuhi, two MÃÂori iwi (tribes), in northern New Zealand in 1807 or 1808. The NgÃÂpuhi force had a few muskets, making this the first occasion MÃÂori used muskets in warfare. The NgÃÂti WhÃÂtua force ambushed the NgÃÂpuhi, and won the battle, which occurred at Moremonui Gully where it enters Ripirà  Beach, south of Maunganui Bluff on the west coast of Northland. It could reasonably be called the first battle of the Musket Wars among MÃÂori, which took place over the next few decades.
The battle of Moremonui was preceded by skirmishes in 1806 between NgÃÂpuhi in the north, led by one of their rangatira (chiefs), Pokaia, on one side, and Kaipara subtribes of NgÃÂti WhÃÂtua in the south on the other. The southern groups were led by TÃÂoho, rangatira of Te Roroa, and Murupaenga, rangatira of the NgÃÂti Rongo subtribe of NgÃÂti WhÃÂtua.
In 1807, Pokaia proposed that NgÃÂpuhi mount a major war expedition against Te Roroa. About 500 NgÃÂpuhi warriors, most from the Kaikohe area and a few from the Hokianga, assembled under Pokaia. In response to NgÃÂpuhi preparations, NgÃÂti WhÃÂtua forces assembled under TÃÂoho, Murupaenga, Te Wana-a-riri of NgÃÂti WhÃÂtua, and Te Hekeua of Te Uri-o-Hau, intending to meet the NgÃÂpuhi before they reached the northern Kaipara. Both sides were armed with the usual striking weapons, but the first European settlement had recently formed at KororÃÂreka in NgÃÂpuhi territory, and a few of the NgÃÂpuhi warriors had acquired muskets.
The NgÃÂpuhi force came down the west coast and camped north of Maunganui Bluff. Alerted that they intended to proceed down Ripirà  Beach at night to camp at Moremonui, the NgÃÂti WhÃÂtua got there first and hid in the Moremonui valley. The unsuspecting NgÃÂpuhi arrived at Moremonui at dawn and prepared a meal. While they were eating, NgÃÂti WhÃÂtua launched a surprise attack. The NgÃÂpuhi scrambled for their weapons and were driven to the beach, where the battle continued for some time. The NgÃÂpuhi muskets were useful, but loading and reloading them took time, and their numbers were not sufficient. Eventually TÃÂoho killed the NgÃÂpuhi leader Pokaia with his mere and the NgÃÂpuhi fled. TÃÂoho had connections with NgÃÂpuhi and, not wishing to completely annihilate them, ordered that a line be drawn in the sand of the beach, beyond which NgÃÂti WhÃÂtua warriors were not to pursue them.
NgÃÂpuhi acknowledged the death of 150 of their party of 500, but other reports of their loss ranged up to 300. Among the dead were Hongi Hika's older brother Houwawe, his half-brother Hau Moka, and his sister Waitapu, whose body was mutilated to symbolise stopping the line of descent. Hongi Hika himself escaped, as did Kawiti, another NgÃÂpuhi leader, due to TÃÂoho's restraint in stopping further pursuit. So numerous were the bodies left on the beach and eaten by gulls, the battle was called Te Kai a te Karoro (the Feast of the Black-backed Gull). This battle is also known as Te Haerenga-o-te-one (the Marking of the sand), named after Te Uri o Hau chief Tieke's act of drawing a line in the sand.
Although only a small number of firearms were used, Moremonui could reasonably be called the first battle of the Musket Wars, as a thirst for utu (justice through revenge) motivated Hongi Hika's campaigns against the NgÃÂti WhÃÂtua over the next twenty years.