I was seeking traces of my relatives. They had been among the first pioneers in Pangatotara, when in 1854 they bought 800 acres along the Motueka River. Major Gascoyne had recently retired from the 5th Bengal Light Cavalry; Isa bella was a mother of seven. They used their soft East India Company hands to carve farmland from the bush, and the farm's failure - along with the handsome governess - wrecked their marriage. There was a scandal. I hoped to find a dwelling that fitted the scanty descriptions I had of "The Bungalow", their two-storey, timber-framed, kit-built abode.

Among Pangatotara's makeshift cabins and modern bungalows, just one looked old enough to have been around in their day. I walked tentatively up the tarmac drive to a cream-painted clapboard cottage, and at a lace-hung window I found an elderly woman tucking a cosy over her teapot. She'd never heard of the Gascoynes. "If I was you," she said, complacently continuing her preparations for tea, "I should think about the present. I wouldn't waste time fussing about what's dead and gone."

The present in New Zealand? Spectacular landscape, wonderful water sports, and not as dull as people say. But still . . . all those samey towns with only the Rotary Club and a Hokey Pokey ice cream to keep you amused. The past, on the other hand: that is far from dead and gone. Only 150 years ago the Gascoynes were living a Dark Age existence here, dragging water from the river and lighting "The Bungalow" with shreds of rag stuck in bowls of fat from the fry-ing pan. Their son Fred spent much of his adult life in the bush fighting medieval-style battles against Maori warriors, but died only in 1926 - well within living memory. This is the recent past, in evidence wherever you look. That is what really makes New Zealand interesting.

The drive south from Auckland had repeatedly invited a sort of double vision, the present only just overlaying the past. It was like meet- ing an old friend after many years, and being unable to forget their youthful looks despite the aged reality.

Rocking along in a camper van, I passed sheep-grazed hills that spoke of the tragic yet heroic felling of the forests, a testament to the settlers' almost superhuman endeavour. I cruised through provincial towns where the parades of low, projecting shopfronts descended directly from the timber-built verandas and fascias of pioneer days. The British toponyms on the road map - Thames, Newcastle, even Cricklewood - seemed banal beside the exotic Maori "Ngatapa" or "Turanganui", but also touchingly echoed the colonists' optimism as they built new lives in Zealandia, the Britain of the south. Every blade of grass, every robin, every trout or deer, every oak tree: all these they had originally packed on board ship and carried 14,000 miles from England, encouraged by the "Acclimatisation Societies" which, from 1868, were founded to make them feel at home (and which thereby caused the destruction of several native species).

Several hours south-east of Rotorua, the secretive mountains of Te Urewera jutted from the plain. They were flanked in virgin subtropical forest: cabbage trees, podocarps and towering straight-trunked pines festooned with wispy lichen, their darkness illuminated by the starburst of tree ferns. Clumps of moss and fern grew on branches, vertical gardens hundreds of feet high. The New Zealand novelist Maurice Shadbolt described how the trees of the Ureweras "suddenly rose around, and there was soil of rancid sort firm underfoot".

I camped beside Lake Waikaremoana. Birds singing do-dee-do-dee-doo loped across the marshes into a sinister impenetrability of green. My cousin Fred Gascoyne lurked here during the New Zealand land wars, scouting for the Maori enemy. He would have wondered nervously who lurked unseen in the foliage. Where were their tomahawks? In his novel Season of the Jew, Shadbolt modelled his hero, Captain George Fairweather, on Fred.

The road dwindled to a dirt track. It clung to the sides of the ravine, and was hacked from the rock in the 1870s by Fred and his troop of Maori Armed Constabulary. Such road-building schemes, already successful in the Scottish Highlands, were used to distract Maori "rebels" from warfare, while also penetrating - and thus destroying - the heart of Maoridom. It worked, but only up to a point: the Tuhoe, who live in the Ureweras, were recently reported to have fired at helicopters carrying in sportsmen to hunt deer. I saw little sign of them, however - just peeling cabins littered with rusting pick-ups, and one Maori meeting house, or marae. No guns.

Off the mountains and down to the Pacific, where Poverty Bay lies spreadeagled between them. Plots of land were being offered for sale as "boutique lifestyle blocks". I couldn't help thinking about Fred who, in 1868, was the only surviving officer of a massacre by the ferocious warrior-prophet Te Kooti. Having escaped from exile on the Chatham Islands, Te Kooti wreaked vengeance on those who had imprisoned him without charge and stolen his land. More than 50 died. In the tiny white church at Matawhero, I found a memorial to the deceased. Fred had to identify and bury their remains.

I crossed the Straits to the South Island and found Nelson a buzz of orchards, wineries and pottery trails. In comparison, the Motueka Valley seemed beleaguered. The Gascoynes had bought some of New Zealand's least fertile land, and it transpired that in 1877 a flood washed it away. Of all the farms that were destroyed that night, the Gascoynes' was the worst; not a single blade of grass was left standing.

Perhaps it is maudlin to dwell on the past. Perhaps I should have taken the old woman's advice, so typically Kiwi in its practicality, and stuck to the present. After all, a radio presenter, announ cing some cultural event, rejoiced that "so much is going on in this great little country of ours". At a supermarket in Nelson the Tannoy alerted me to the special offers, then wished me "an awesome day" in God's Own Country.

Helena Drysdale's book "Strangerland: a family at war" is published by Picador (£14.99)