"It's been a very draining five years. The settlement involved some payment but was less than the legal costs would have been for the scheduled six week hearing," Dr Smith said outside court.
A six-week hearing was due to start in the High Court at Auckland yesterday but was delayed as the parties continued talks.
Timber preservatives producer Osmose New Zealand alleged the Nelson MP and timber preservation scientist Robin Wakeling defamed it.
Osmose New Zealand, a division of a US-based wood preservation corporation, alleged that statements made in July 2005 about the company's surface-treated timber product, T1.2, destroyed the product's reputation and the company lost more than $14 million in projected profit.
Counsel for the parties appeared in the High Court today to announce an agreement had been reached, but the terms were confidential.
Dr Smith said that no public money was involved in the settlement.
"Although I've been very grateful to have received $209,000 of public money from Parliamentary Service, given that the work involved my work as the then opposition spokesperson on building and construction.
"The cost to me personally is in excess of what it has cost the public purse. Sometimes that's the price for standing up for what you believe in," he said.
Dr Smith thanked his counsel who he said had been a huge support to him in reaching the settlement.
"I'm pleased to have it behind me so I can focus on my job as being MP for Nelson and my ministerial roles.
"It is a huge relief and I also want to acknowledge Dr Robin Wakeling, who has been the other key defendant in this matter.
"I have huge respect for his integrity, and he like me, is pleased to have this behind him," he said.
Dr Smith refused to answer questions about whether he had lost credibility or whether justice had been done, and said people would judge for themselves.
"It's inevitable in the rough and tumble of politics that sometimes you're involved in these sorts of proceedings," he added.
He said the cost to him personally had been in excess of the $209,000 including the legal expenses of the past five years, and the payment he would be making as part of the settlement.
Dr Wakeling said he was also relieved that it was all over.
"Five years of defamation proceedings is tough. It does take an emotional as well as a financial toll. I was forced to represent myself, although I had a lot of help from my counsel early on, but I had to make the difficult decision that I couldn't afford counsel for a six week trial," he said.
Dr Smith's lawyer, Peter McKenzie QC, read out a statement of apology from his client in court to Osmose New Zealand.
"I apologise for having made public statements that did not fully represent the position in relation to TimberSaver. In particular, I now accept I overstated the risks associated with the use of TimberSaver; that the problems were with the marketing of timber, and ensuring the conditions of use were complied with, that were not primarily the responsibility of Osmose and that, as a result, some of the statements I made were incorrect and unfair to Osmose," he said.
Justice Rhys Harrison acknowledged an agreement had been reached and struck out the proceedings.
"I would like to congratulate the parties for reaching a sensible resolution," he said.
He also acknowledged the presence of Dr Smith and Dr Wakeling in court and congratulated them on reaching a compromise.
It was revealed in April that Parliamentary Service had contributed $122,000 towards the then total of $270,000 in costs faced by Dr Smith.
Prime Minister John Key said Dr Smith had acted in what he thought was the best interest of New Zealanders and the use of taxpayer funds was "totally legitimate".
