The afternoon talk-show host has been off air this week after stand-in host John Banks last month endorsed the views of a caller who described Māori as "stone-age people with a stone-age culture".
The racist dialogue caused an uproar. At least one major corporate suspended advertising with the station and New Zealand Cricket, that had only just signed a three-year broadcasting partnership deal, threatened to review its relationship with Magic Talk.
Banks was replaced and Wallace announced the fill-in broadcaster would never get another job at the station while he was at the helm.
But as colleagues distanced themselves from the former Auckland mayor, Plunket posted a tweet appearing to sympathise with the outspoken broadcaster and former mayor.
The radio personality was asked not to return to Magic Talk and management were reported to be in crisis talks.
Plunket's show Magic Afternoons with Sean Plunket ran weekdays from midday-4pm.
It had courted controversy in the past year, earning a stiff rebuke and a fine from the Broadcasting Standards Authority over allegations of racism.
In December, the BSA rebuked MediaWorks after a May 6 Plunket interview with Te Whānau ā Apanui spokesman Louis Rapihana on Covid-19 checkpoints.
The BSA said the interview amplified negative stereotypes about Māori and had the potential to cause widespread harm.
The Herald has approached Plunket for comment.
