A single judge of Kerala High Court held as follow:

From Para 29-32, (Regarding issuing of arrest warrants without following procedure u/s 421 Cr.P.C.)

29. Now, coming to the next question regarding the failure of the Family Court in not following the procedure for levy of fines as contemplated under Section 421 of the Code.
30. Section 125 (3) extracted above, stipulates that in case of failure of a person to comply with an order to pay maintenance without sufficient cause, then for every breach, the Magistrate has to issue a warrant for levying the amount due in the same manner provided for levying fines.
32. It is well-settled in a whole line of precedents that the Courts shall not order a warrant of arrest against a defaulter, without following the procedure under Section 421 of the Code.

From Para 33,

33. Nonetheless, after the pronouncement of the celebrated judgment in Rajnesh v. Neha (supra), a revolutionary change has been brought in the procedure to be followed by the courts in dealing with the applications filed under Chapter IX of the Code. The Hon’ble Supreme Court has issued comprehensive procedural and normative directions streamlining the maintenance laws, inter alia, directing that the parties in a maintenance application have to file affidavits of disclosure of their assets and liabilities, which must be considered by Courts while deciding the application. It is also held that, in case of a dispute on the declaration made in the affidavits of disclosure, the aggrieved person can seek leave of the Court to serve interrogatories on the opposite side and seek production of relevant documents as provided under Order 9 of the Code of Civil Procedure, and in case a false statement or misrepresentation is made, the Court can initiate proceedings under Section 340 of the Code or for contempt of court.
34. In the instant case, the Family Court, following the directions laid down in Rajnesh v. Neha (supra), directed both parties to file their affidavits of disclosure in the original proceedings. The revision petitioner filed his affidavit stating that he had no movable or immovable properties. Again, on the execution side, the Family Court directed the first respondent to file an affidavit regarding the assets of the revision petitioner, and she reiterated that the revision petitioner had no assets or properties. Based on the affirmation in the affidavits, that the revision petitioner had no movable or immovable properties, the Family Court issued a non-bailable warrant against the revision petitioner. I do not find any error or illegality in the procedure adopted by the Family Court in the post-Rajnesh era. Once a party declares on oath that he has no movable and immovable properties, it would be an empty formality to follow the procedure under Section 421 because, ultimately, the enquiry by the revenue authorities would yield the same result as disclosed by the parties on solemn affirmation. The exposition of the law in Rajnesh was to remove the stumbling blocks in the procedure and the inordinate delay being caused in the disposal of maintenance applications and the enforcement of the orders. It is trite, that procedural laws are handmaids of justice. Therefore, the dispensation of the procedure under Section 421 of the Code, in a case where the respondent disclosed that he has no movable or immovable property, is justifiable and sustainable in law. In the emerged scenario post Rajnesh, I do not find any meaningful purpose in the Courts ritualistically following the procedure under Section 421, especially after the respondent states on oath that he has no property, other than to prolong the miseries of the persons living in vagrancy.

Index of Maintenance cases here.