PORT Adelaide has locked in young guns Connor Rozee, Zak Butters and Xavier Duursma on two-year contract extensions until the end of 2022.

The Power have also signed 20-year-old defender Joel Garner for another two years until the end of 2021, while untried forward Jake Patmore has signed a new one-year deal for 2020.

Rozee, Butters and Duursma were already under contract until the end of next season, but the Power jumped at the chance to secure the exciting prospects.

All three first-round draft picks from the 2018 NAB AFL Draft have made an immediate impact.

Rozee and Duursma have played every game this season, while Butters has played all but one match.

The Power selected Rozee with the fifth overall pick at last year's draft before nabbing Butters with pick 12 and Duursma with pick 18.

Rozee is the Power's leading goalkicker with 20 goals this season, his highlight coming in round three when he booted five goals in his side's loss to Brisbane at the Gabba, which earnt him a nomination in the NAB AFL Rising Star award.

Duursma's ability to cover the ground on the wing has been phenomenal and he's covered the most distance of any Power player this season.

He was the round six nominee for the Rising Star award when he had 24 disposals, eight marks, three inside 50s and a goal against North Melbourne in round six.

Butters has kicked eight goals in his 14 games playing as a half-forward, while also averaging 15.4 disposals per game.

Garner - the 60th overall pick in the 2017 national draft - has played three games this season after making his debut in the round nine win against Gold Coast.

Patmore - the 58th pick in 2017 - is recovering from a torn ACL suffered in a pre-season trial match this year.