A strike launched Friday by workers at the South African Diamond and Precious Metal Regular offices in Johannesburg has kept a shipment of diamonds worth over $75.3 million from being shipped to London for aggregation, according to South Africa's Business Report.

The employees are demanding a 10% increase in wages and an increased housing allowance and say that management has taken too long to respond to their demands. In a meeting Thursday evening, management reportedly offered a 9% salary increase but no change to the housing allowance.

The Business Report quoted Diamond Regulator CEO Levy Rapoo saying that the company had not expected the strike and noting that it was "regrettable" that the people who were striking were the ones responsible for exporting the country's diamonds.

The Diamond Trading Company notified its clients that the export would not go ahead as planned.