The correct phrase is "temporary basis." This refers to a situation or arrangement that is not permanent and is established for a limited time. "Bases" is the plural form of "base," which would not be appropriate in this context.
The singular form is "basis" and the plural form is "bases".
The plural of basis is bases (bay-seez).
The plural of basis is bases
A bag valve mask is used to manually breathe for the patient on a temporary basis.
They hired me on a temporary basis until the supervisor returns from maternity leave.
Bases.
Usually, they ruled with the intent of it being a permanent basis.
Fix-a-Flat kits work on a very temporary basis. A punctured tire should be replaced.
There is no limit to the length of time a client can employ an employee as a temporary or contingent worker (on a W-2 basis; 1099 contractors may have different rules). Temporary workers are considered employed on a "at-will" basis.
The plural of basis is bases (pronounced bās'ēz).
The plural of basis is bases (pronounced bayseez).
The word basis is singular. The plural is bases.