The arrival in August 1860 of Major-General Thomas Pratt heralded the development of a new strategy to break the cordon that encircled New Plymouth.
The town was now crowded with thousands of terrified settlers and ‘embarrassed soldiers’. Living conditions deteriorated to the point that disease posed a greater threat than warfare. As many as 121 people died from diseases such as scarlet fever during this period. Settler farms continued to burn and a number of settlers, including children, beyond the safety of the town were killed. More settlers were evacuated to Nelson and Auckland.
Governor Gore Browne was under pressure as matters went from bad to worse in Taranaki. In July he invited 200 chiefs (Kingi and the new Maori King, Tawhiao, were not among them) to Kohimarama near Auckland for what was primarily intended as a discussion on the Treaty of Waitangi. Gore Browne also sought to gauge tribal opinion on Taranaki in a bid to isolate Kingi and his allies. Many of those present criticised him for waging war, especially on the flimsy grounds that Kingi had no customary rights to Waitara. The Crown was rebuked for its ‘indifferent regard for the Treaty of Waitangi’.
Some of the pressure was eased during spring. Pratt, with 1400 men now at his disposal, set about destroying pa north and south of New Plymouth. These were generally empty but action did help create an illusion of progress. The reality of part-time warriors versus a professional army became apparent as Te Atiawa warriors returned home to plant crops for the following season.
In early November 150 Ngati Haua reinforcements led by Wetini Taiporutu arrived in Taranaki. These warriors wanted to ‘kill soldiers themselves.’ Wetini and his men arrived at the old pa site of Mahoetahi, a ‘small volcanic hump’ between New Plymouth and Waitara, on 5 November. The next morning they were caught unawares by Pratt and a force of 1000 who by pure coincidence were planning to occupy the same site. With their defences incomplete the Ngati Haua garrison was quickly routed. Nearly a third of the Maori force was killed.
Mahoetahi was not the decisive victory Pratt craved. More importantly, this was a Waikato defeat – the Te Atiawa force remained largely intact. One newspaper summed up the significance of Mahoetahi by acknowledging that while there was ‘nothing connected with the engagement of which we can boast … we have, during the course of this war become so accustomed to ignominious defeats that even this small victory is welcome.’
Mahoetahi was of little strategic value. Pratt now decided that instead of sporadic assaults on Maori positions he would seek to bring continuous pressure to bear on the Maori cordon by using the systematic siege warfare tactic of sapping. A sap – a long, covered trench – would be dug along the rising ground west of the Waitara River, allowing men to advance without being exposed to direct fire. A series of redoubts covering the sap would either force the Maori back or tempt them into a risky attack.
Sapping was hard work. It was also too slow for the liking of many settlers. A sap might progress at the rate of only 60 m a day and in the meantime attacks against settler property continued unabated. Settler lives were lost in these attacks while Pratt's sapping continued. Little was achieved in lifting the siege on New Plymouth and 51 settlers died of disease in the opening months of 1861.