MARLEY Williams' career-reviving switch to North Melbourne continues to pay dividends, with the zippy defender earning a one-year contract extension.

The former Magpie, who was at risk of being delisted by Collingwood last year before being traded for pick 105, is now tied to the Kangaroos until at least the end of 2019.

"I’ve loved everything about North and feel right at home at the club," Williams said.

"There’s a lot to like about this footy club - the players, the environment and what lies ahead - I’m really happy with the contract extension and owe North a hell of a lot.

"It’s a great show of faith to me by the club and some reward for the effort I have been putting in. I’m thrilled to be able to get an extra year.

"It’s been a fresh start and I’ve been able to play every game prior to hurting my back.

"The change of scenery has really helped with starting over and freshening up. I started back at the bottom and have tried to work my way back to the top."

Williams has played every game for the Roos this season except last round's loss to Gold Coast due to a back strain.

The 23-year-old will also miss Sunday's clash against Fremantle.

Senior coach Brad Scott said Williams has established himself as a reliable part of North's backline.

"We couldn’t have asked for more from Marley both on and off the field," Scott said.

"He’s been a real rock in defence for us, playing in almost every game so far and shutting down some of the AFL’s most explosive forwards.

"He’s never beaten in the contest and never gives up, no matter the circumstances.

"We were delighted when we were able to sign him late last year, and were are even more delighted now given what he's provided to the team and the club."

Williams, who is averaging 18 touches a game, played 68 games for Collingwood and finished seventh in the Copeland Trophy count in 2015.

But the former rookie, from Albany in WA's south, fell out of favour last season.

A foot injury in round three sidelined him for five games, and Williams was later dropped twice as his form tapered.

He finished the season at AFL level but his kicking let him down.