The Logan's Run star appeared as Tessa Phillips from the start of the BBC spy drama, with her treacherous character leaving the country towards the end of the second season.
When asked if she ever considered coming back to the programme, Agutter told Digital Spy: "Ooh, absolutely. Tessa's not dead yet! It's just about finding the right story. I think it's been mentioned, but we'd have to find something.
"It'd be nice to do. I think there's a lot to get sorted out with Harry, don't you? There's the possibility for a good battle there again!"
She added of the show, which is currently filming its ninth series: "I do think it's always had good writers and they do really do keep it moving along and it's riveting, it's good stuff."
Agutter rose to fame as Roberta in the 1970 movie The Railway Children, which has been digitally restored for a cinema release on April 2 ahead of its DVD and Blu-ray release on May 3.