Hawke's Bay have kept their Ranfurly Shield defence rolling, producing their most dominant performance of the year to leave Southland staggering.

The Magpies ran in 10 tries - five of them to their hookers and four from the maul - as they retained the Log O' Wood for the 14th time.

Another success against Wellington next week would see Hawke's Bay equal the 15-match reign of Canterbury from 2004 to 2006 as the second-longest defence this century.

They would then be in position to make it a sweet 16 in their final home match of the season against Tasman, when another win would see them lock away the Shield for another year.

They were never in danger of letting it slip against a winless Southland at McLean Park today.

Supreme at the set piece and deadly when they spread the ball, Hawke's Bay turned a narrow halftime lead into a comfortable victory with a six-try blitz in the second spell.

The lineout drive, in particular, was an unstoppable weapon for the Magpies, with their variations proving far too tough for Southland to handle.

Starting hooker Tyrone Thompson finished off two rumbling mauls - and added a third try after another clinical attack from a lineout - before substitute Kianu Kereru-Symes crashed across twice more.

"It's unreal," Thompson told Sky Sport. "The boys were mean today. We seem to always turn up when it's at home.