Very interesting question - both from a theoretical and practical perspective. I have come across this term very often in American legal systems where "Cause of Action" is a common basis to seek dismissal of a suit. A motion to dismiss as it is usually called there. There is a parallel theory called Summary Judgment - Based on the facts the Court can decide the case without going to trial. I googled the term "cause of action" and here is what Wikipedia says:
In the law, a cause of action is a set of facts sufficient to justify a right to sue to obtain money, property, or the enforcement of a right against another party. The term also refers to the legal theory upon which a plaintiff brings suit (such as breach of contract, battery, or false imprisonment).
Your maintenance application, like any suit/petition or application or motion, would be based upon certain facts and the applicable law. Let us say that there are 40 paragraphs of which 30 allege facts and 10 provide the legal basis and the prayers to provide relief (maintenance in your case). If you are able to show that out of the 30 factual assertions made, 29 are false, you are still left with a petition/application with 1 fact and that may be sufficient to seek maintenance. In other words, falsified facts do not necessarily wipe out the cause of action. Also, percentage of falsity is not relevant. What is important is the relevance of undisputed facts - facts admitted by both parties. If there is one paragraph that states that you were married on so-and-so date and that is true and all other allegations are false, then the maintenance application will survive and will not be dismissed in limine (that is, at the very outset). Other facts will come out in trial at the end of which the Judge will decide the case.
DISCLAIMER: I AM NOT AN ADVOCATE....