Opposite of "As early as possible"

My manager asked me to finish the project as early as possible

Here there is no fixed deadline available but the manager wants me to finish the project soon. Consider the case where there is a deadline but I can take as much time as I want before the deadline to finish the project. In this case, is it appropriate for a person to say, "You can finish the project as late as possible (meaning, you have time to do), but do it before the deadline expires"?

I am looking for an exact opposite phrase for as early as possible. If it is not there, is there a phrase which can capture what I have mentioned in the above mentioned paragraph?

Solution 1:

In business context, I would say, "Finish the project when (whenever) it is convenient for you before the deadline".

I have never heard someone say, "Please finish it as late as possible" which would be understood as the speaker wants you to finish the project at the latest moment before the deadline.

But, if you say "when it is convenient for you", it doesn't impose any urgency and the speaker can wait until it is finished before the deadline.

Solution 2:

I would say "at your convenience". This gives the impression that the person should complete the work but within the time period he is comfortable and fits into his schedule.

E.g.,

Please complete the project at your convenience, but keep in mind the deadline.