Police have seized more than a kilogram of explosives and arrested 11 people during operations targeting organised crime in Sydney's west.

Strike force Crewe, set up to investigate drug crime, has carried out a series of raids since Tuesday in suburbs surrounding Parramatta.

Police arrested a 49-year-old woman and a 23-year-old man at Fairfield, as well as a 41-year-old man at Bonnyrigg yesterday.

The 41-year-old has been accused of selling banned firearms, drugs and ammunition.

This was followed by more raids in suburbs including Heckenberg, Meadowbank, Greystanes and Harris Park during which eight men were arrested.

Police also seized a haul including drugs, guns, ammunition, money, 1.25 kilos of explosives and two detonators.

The men have been refused bail and are due to appear before Fairfield Local Court today.