See - REMULLA VS. MALIKSI, GR NO. 171633, SEPT. 11, 2013.
"x x x.
With respect to the first, jurisprudence dictates that a taxpayer may be allowed to sue where there is a claim that public funds are illegally disbursed or that public money is being deflected to any improper purpose, or that public funds are wasted through the enforcement of an invalid or unconstitutional law or ordinance. 34 In this case, public funds of the Province of Cavite stand to be expended to enforce the compromise judgment. As such, Remulla – being a resident-taxpayer of the Province of Cavite – has the legal standing to file the petition for annulment of judgment and, therefore, the same should not have been dismissed on said ground. Notably, the fact that there lies no proof that public funds have already been disbursed should not preclude Remulla from assailing the validity of the compromise judgment. Lest it be misunderstood, the concept of legal standing is ultimately a procedural technicality which may be relaxed by the Court if the circumstances so warrant. As observed in Mamba v. Lara,35 the Court did not hesitate to give standing to taxpayers in cases36 where serious legal issues were raised or where public expenditures of millions of pesos were involved. Likewise, it has also been ruled that a taxpayer need not be a party to the contract in order to challenge its validity, 37 or to seek the annulment of the same on the ground of extrinsic fraud.38 Indeed, for as long as taxes are involved, the people have a right to question contracts entered into by the government,39 as in this case.
x x x."
