As Scampl has noted, ISO 17025 is a standard for laboratory analysis. A laboratory that has been accredited to this standard is highly regarded as they perform their tests to the required certified standard. This means that any laboratory tests captured under this certification have been validated to the required analytical standard and you should expect any certified lab for that test to produce near identical results on the same sample.
Down under any Lab that is certified to this standard is typically certified by NATA - National Association of testing Authorities Australia. Note however even thought they are certified to this standard some of their analytical tests methods may not be certified to the specific standard for that analytical method. So where a lab is certified to the ISO 17025 standard you need to understand the scope of that certification and what analytical methods are captured in that certification.