Appearing on The Graham Norton Radio Show with Virgin Radio, the Ted Hastings actor hinted that the next series, which will see Kelly Macdonald take over as the show's lead, could arrive "within the next couple of months".
But will AC-12's investigative adventures continue beyond that?
"I think as long as there's an appetite from our audience for the show, we'll keep going," Dunbar told Graham Norton.
"Why would we stop? We've managed to keep the standard, Jed [Mercurio, show creator] rather, has managed to keep the standard so high for so long, and people love the show. I hope it does go on."
He added: "But of course everything is finite, I see Peaky Blinders is coming off after six fabulous seasons. When it ends, it will end, and we'll have all had the most wonderful time."
Back in 2017, before the release of series 5, Mercurio expressed a desire to keep developing the story beyond season 6, telling the Radio Times: "At the moment there is a great appetite among all of us involved in the programme to do more.
"What we don't know is whether there will come a point where we kind of lose that enthusiasm to keep going back."
Line of Duty airs on BBC One. Series 1-5 are available on boxset now.
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