Sir Richard Hadlee has hailed Kane Williamson's world Test champion side as the best in New Zealand's cricketing history, describing its performances in the past two years as simply "outstanding".

New Zealand defeated India by eight wickets to be crowned the first-ever world Test champions in Southampton on Wednesday night, their first-ever ICC title.

"This is a special day in the history of NZ cricket, a day to celebrate the magnificent achievement of winning the inaugural World Test Championship," Hadlee said in a statement.

"It was a thrilling Test match, with twists and turns throughout...it was a dominant BLACKCAPS performance over a very good Indian team. Over the years NZC have built a significant depth of players, which makes us one of the most competitive teams in world cricket.

"It's fair to say that this current group of players is the best in our history," he added.

The iconic pacer, who was the first bowler in international cricket to take 400 Test wickets, said the victory is a reward for two years of excellence.

"Over the past two years, the BLACKCAPS performances in the Test arena have been outstanding with Test match and series wins at home and abroad, and they thoroughly deserve to be crowned world champions."

"The whole team has shown a high degree of professionalism. Their skill sets have complimented each other to make them a complete playing unit."

"The management and support staff have also played important roles in preparing players to perform at the highest level," he added.