Wages are protected by MLC 2006 Standard A2.2: payment must be in full, in legal tender, and at intervals not exceeding one month. Lawful deductions are limited (income tax where applicable, social-security contributions where applicable, allotments authorised by you, properly-documented loans against wages). Anything else — including 'training fees', 'agency fees', 'visa fees', or unilateral charges for damaged stores or ship's property — is unlawful. ILO Convention 173 (Protection of Workers' Claims) reinforces this. Keep every wage account; demand corrections in writing.
MLC 2006 Reg. 2.2 (wages) and Standard A2.2 (regular and full payment). ILO Convention 173 (Protection of Workers' Claims). ILO Convention 181 (Private Employment Agencies, Article 7 — no fees to workers). National labour codes set wage protection standards specific to each jurisdiction.