Recently in Wong v McDonald [2015] FCCA 2120 the Federal Circuit Court of Australia affirmed that although guarantees are instruments to be strictly construed, where there appears to be any ambiguity of a term, the Court must firstly determine the ordinary business meaning of the written contract before deciding there is an ambiguity at all.

In this case the trustee in bankruptcy rejected a proof of debt on the basis there was an ambiguity as to the existence of an obligation by the guarantor to pay and the guarantee creating an enforceable obligation.  The Court found that although the principal debt was not expressly identified, to construe the document as not giving rise to any obligation to repay the debt would be to defeat the clear objective intention of the parties to create an enforceable right and the provisions should, in those circumstances, be inferred.

The ordinary business meaning from the language of the instrument created a real enforceable obligation of liability even though the instrument failed to make express provision for a certain matters.