The Melbourne Rebels' horror Super Rugby season continues, with a demoralising 51-12 loss to the Highlanders.

With Australian conference places in doubt for 2018, the Rebels did themselves no favours in an embarrassing display at Dunedin's Forsyth Barr Stadium on Friday night.

The capitulation to the last-paced Kiwis completes a clean sweep of losses against New Zealand teams, after also going down to the Blues, Hurricanes and Chiefs in a winless start to their campaign.

A week ago against the Waratahs, Melbourne delivered their best half of the season but the first 40 minutes against the Highlanders was their worst.

The home side raced to a 20-0 lead at the break through two tries and the boot of five-eighth Marty Banks.

The Rebels' opening stanza statistics were the stuff of nightmares for coach Tony McGahan.

They only had 37 per cent of possession and territory and looked lazy in defence with 13 missed tackles to the Highlanders' four.

They lost two tightheads, which led to the tries and made 10 handling errors which meant they were unable to build any pressure.

While praising the effort and execution of their opponents, McGahan said his team were their own worst enemy.

"The Highlanders were very clinical in what they did. They kicked really well, were really strong defensively, played good field position and put us under immense pressure on both sides of the ball and really strangled us in the end," he said.

"But if you go through their tries most of them originated from us with the ball so we contributed a lot to that.

"To be fair their pressure was excellent and they really tore into us."

Winger Tom English scored in the 52nd minute and Reece Hodge in the 79th in a couple of bright moments but the rest of the second half was one way traffic, much like the first.

The Highlanders ran in a further four tries as they locked away their bonus point, with centre Malakai Fekitoa adding a second after also opening the scoring.

A converted try by reserve hooker Greg Pleasants-Tate after the final hooter nudged his team's tally past the half century mark.

The win was a fitting way to celebrate halfback Aaron Smith's 100th Super Rugby game.

The Rebels have their second bye next week, before a match against current Australian conference leaders, the Brumbies, in round eight.