"a needed basis" is correct and usable in written English.
You can use it to refer to something that is provided due to necessity. For example: "The company will operate on a needed basis until the proper resources are acquired."
NSW has been named a standout state by experts including Bonnor for allocating Gonski funding on a needs basis and directing money to the most disadvantaged schools.
On a needs basis, some treatment centers may provide partial financial assistance through various scholarship funds to patients who qualify for such assistance.
The UK's levy would come from our already assigned foreign aid budget and be allocated to humanitarian agencies on a "need" basis ensuring that money is not withheld and humanitarian needs are met.
Employers should ensure that at least some funded internships are set aside on a needs basis and make it clear to university career centres that they are interested in addressing the existing underrepresentation of poorer aid workers.
Some of the prime minister's colleagues had called for the priority to be Christians, prompting Labor and others to declare that the places should be allocated "on a needs basis, without qualification or discrimination".
For example, I may delegate certain information access on a needs basis.
These can be developed on a needs basis, together with identified partners, with the support of the UNISDR Science and Technology Advisory Group.
Patients should be treated on a needs basis, rather than be put on a queue and told to wait in line.
Critics described this as 'development as counter-terrorism', arguing that aid should be disbursed on a needs basis and not 'according to Whitehall's security agenda' [ 68].
