A NAB does not automatically gain international recognition but has to demonstrate competence to peers by conducting assessments and issuing certificates. Potential clients may prefer well-established ABs, and to overcome this, newly established NABs may enter temporary 'twinning agreements' with established NABs to fast-track the recognition process.
Financial sustainability of NABs may be a challenge. Accreditation is not free, and accredited organisations need to pay the NAB an annual fee over and above the initial accreditation costs. As accreditation is not for profit, Government may need to bear costs for the AB until such time as it can be self-sustaining.
Difficulty in training and maintaining proficiency of assessors. Assessments for accreditation must be conducted by trained and registered assessors. Training of assessor must include practical experience of conducting assessments. These may not be easily organised due to a lack of organisations ready for accreditation.
Some private laboratories (even if unaccredited) may be more recognized.
