Mid next week, mid week

I see people write middle of next week as "mid week" or should it be "mid next week?"
What is the simple and correct way to write " the middle of next week".

May I write - "I will send the package before the middle of next week" as "I will send the package before mid next week"?

Solution 1:

The clearest way to state something is going to happen the middle of next week, would be to write it as "middle of next week". There's nothing wrong with it, its concise, brief, and easily understood:

So, you may write:

I will send the package before the middle of next week.

Edit:

However, people often do use "mid-next week". This will also be understood.