Taking into account the time already served in prison, the 56-year-old will spend at least eight more years inside before he is eligible for parole.
A seven-week trial in the High Court at Wellington was followed by a tense wait of more than two days for the jury to return verdicts.
But when they did yesterday afternoon, the news provided relief for Lundy's brother Craig, who said while there was some solace in the guilty finding, "the loss of our loved ones will always remain with us".
Christine Lundy, 38, and daughter Amber were found hacked to death in their Palmerston North home on the morning of August 30, 2000.
"For the past few months we have had to relive the moment we were told a despicable human being took the lives of our much cherished sister-in-law Christine, and our beautiful niece, Amber," Craig Lundy said.
He was full of praise for the police, who in turn commended prosecutors for presenting the case in court.
"I want to acknowledge Crown Law and the investigation team who have worked diligently for more than 18 months, carefully reviewing evidence and preparing for trial, as well as the witnesses and experts who have contributed their time and expertise to this trial," Detective Inspector Marc Hercock said.
Despite the tension around court yesterday afternoon, there was little reaction when the verdict arrived.
Lundy stood with his mouth slightly open but was led away without a word or gesture when convicted by Justice Simon France.
He was similarly expressionless as he was brought back into court moments later, when the judge opted to sentence him on the spot.
Lundy's old sentence of life imprisonment with a minimum non-parole period of 20 years was re-imposed and, within minutes, he was driven from court in a white van with tinted windows.
While police fronted media outside court, Crown prosecutors Philip Morgan, QC, and Ben Vanderkolk left without comment.
Lundy's legal team - David Hislop, QC, Ross Burns and Julie-Anne Kincade - made a less public exit from a side door. Later, Mr Hislop said he had not considered an appeal of the guilty verdicts, but did not rule it out once the "dust settled".
Also reluctant to speak to the waiting media were Lundy's sister and brother-in-law Caryl and Dave Jones, with whom Lundy had been on bail for the past 18 months.
Christine Lundy's brother Glenn Weggery, who the defence fingered as the murderer when he gave evidence in the first week of the trial, was absent after following much of the case from the public gallery.
Her friend Christine Lockett said the jury had "absolutely" got the right verdict and an acquittal would have been "just devastating".
The re-trial had been "an upheaval" for friends and family but Christine and Amber had justice.
"There's two very special people who are not with us today that should be here, but they're not, so this is justice for them," Mrs Lockett told Radio NZ. She said she never wanted to see or speak to Lundy again.
"He is the most vulgar man on this earth as far as I'm concerned."
Prime Minister John Key said the jury had heard all the evidence and had "spoken quite clearly".
"People always accept that a good part of the judicial system is the opportunity for people to appeal if they genuinely believe the wrong verdict has been delivered.
"In this case, the jury has had an opportunity to hear all of the evidence again, strongly made by both sides, and they've spoken quite clearly."
One man happy to voice his disgust at the verdict was one of Lundy's most loyal supporters, Geoff Levick, a retired businessman who spent years researching the case and helping with the Privy Council bid.
"It's going to take a little while to sink in and digest. But I'm extremely disappointed and more than a little angry," he said.
He confirmed he had recently fallen out with the defence team and said he had nothing to do with preparations for the trial.
What Crown says Lundy did on August 30, 2000
There was no smoking gun in the case against Mark Lundy, but the totality of the evidence convinced the jury he was the killer.
That was how prosecutor Philip Morgan, QC, summed up the case in court last week.
"The car tells us how far he travelled, the shirt tells us where he went and who he did this to, the paint flakes tell us what he did it with, the scene tells us what he did, Witness X tells us why Amber had to go too, and the finances tell us why," Mr Morgan said.
The Crown says Lundy left wife Christine and 7-year-old daughter Amber in Palmerston North on August 29, 2000, as he took one of his regular work trips to Wellington, where he sold kitchen sinks.
He checked into his Petone motel that evening where, not long after, he received a call from his wife to say Amber's Pippins (junior Girl Guides) had been cancelled and they were getting McDonald's for dinner.
As he usually did during his motel stays, Lundy bought a meal from a nearby supermarket and ate while watching television in his room.
That evening - knowing he would drive 150km home in the early hours of the morning - he moved his car, so as not to wake other guests.
He sank some rum. The prostitute who visited him just before midnight said he stank of it.
And when she left, just before 1am on August 30, Lundy made what the Crown referred to as "the killing trip".
When he arrived in Palmerston North he retrieved a tomahawk or small axe from his shed and entered 30 Karamea Cres.
He found Christine naked and asleep in their bed and began chopping at her with the weapon with such force that paint flecks from it embedded themselves on fragments of skull and blood splattered high up the walls.
Amber walked in and she, too, was hacked to death, her body left in the bedroom doorway.
To make it look like a burglary, Lundy grabbed his wife's jewellery box and left a window open on which Christine's blood was found.
He then made the drive back to Petone where he slept and began work the next day, visiting customers and fronting as "the genial sink salesman".
- Rob Kidd/additional reporting: Jared Savage and Audrey Young of the Herald, John Weekes, Nikki Papatsoumas, Rebecca Quilliam and Sophie Ryan of NZME. News Service
