The 1890 Australian maritime dispute was an industrial dispute that began on 15 August 1890 when the Mercantile Marine Officers' Association directed its members to give 24 hours' notice to their employers after negotiations broke down with the Steamship Owners' Association of Victoria over longstanding pay and conditions claims. Industrial action quickly spread to seamen, wharf labourers, then gas stockers. Coal miners from Newcastle, Broken Hill, and even New Zealand were locked out after refusing to dig coal for non-union operated vessels. By September 1890, 28,500 workers were on strike.
The Melbourne branch of the Marine Officers' Association had joined the Melbourne Trades Hall Council, and the New Zealand branch was affiliated with the Maritime Labour Council. In July 1890 the Union Steamship Company of New Zealand had conceded a pay rise of one pound, following arbitration. Many of the owners had privately conceded that an increase in pay was justified and overdue. The Sydney branch of the union, not affiliated with the Sydney Maritime Council, negotiated with the owners and were told their case was reasonable, but could not be considered while the Melbourne branch was affiliated with Melbourne Trades Hall. In a last minute mediation, officials of the union agreed to withdraw from the Melbourne Trades Hall, if employers agreed to compromise in a last minute meeting with a union delegation. The Shipowners refused to meet the delegation, which thus precipitated the strike.
Ostensibly over pay and conditions, the causes of the dispute were considered more complex, and point to an employer conspiracy to render trade union activity ineffective, and employer activity to counter union solidarity in secondary boycott of non-union shorn wool in the pastoral industry. While some historians argue that the strike was caused by a downturn in economic conditions, others argue the depression of the 1890s did not start till 1892.
In early July 1890, the Amalgamated Shearers' Union had issued a manifesto calling a boycott on non-union wool shorn in the coming shearing season. This emulated a successful boycott of non-union wool called by the Queensland Shearers Union in 1889 and instituted by the Wharf Labourer's Union and Brisbane Trades Hall. The conspiracy to break union solidarity was engineered by stevedore Alfred Lamb, a member of the New South Wales Legislative Assembly, owner of one of the four main wool exporting firms, and vice president of the NSW Employers' Union. He attended meetings of the Pastoralists Union of NSW, the Pastoralists Union of Victoria, organised a memorandum of understanding and agreements among wool shippers, shipping agents and shipowners.