Could parental refusal of newborn screening be overridden by a court?

It is routine practice in all jurisdictions in Australia to screen newborn infants for certain genetic conditions by a heel prick blood test (Guthrie test) a few days after birth. However, testing is not compulsory here, nor in New Zealand or the United Kingdom, unlike in the USA. This means that parents in Australia are legally entitled to refuse permission for their child to be tested (although, as explained later, that refusal could be challenged in a court). Without parental consent, or other lawful authority, taking blood for testing would constitute a battery (trespass to the person, colloquially called ‘assault’), for which the parents could sue the person taking blood and his or her employer.