The 30 plus workers who are members of the Unite union are employed by Sasse Ltd on an outsourced contract.
The staff, who are currently paid £10.90 an hour, have rejected a pay increase of 5% for day workers and 7% for night workers.
As a result, the union has announced two initial 24-hour strikes beginning at 6:30am on Friday 11 August, with the second strike taking place from the same time on Wednesday 30 August.
Unite general secretary Sharon Graham said: "Sasse has been caught red handed. It is prepared to pay out huge amounts in dividends, yet it doesn’t believe it is necessary to give its very low paid cleaners a fair pay increase."
