Formal(honorific) = 방해 안할게요 or 일 보세요. If person you are talking to is in the same age or lower than you = 방해 안할게 or 일 봐 You can also attach two sentence and say it continually like '방해 안할게요, 일보세요.' It is 'I won't bother you, take care of your work( job, task, etc ) in English.

방해하지 않을게