Workers who make Taubmans, Bristol and White Knight paints have accused the company of "starving them out" as its lockout of staff now stretches into a fourth month.

Multinational PPG gave 57 workers written notice they would be locked out of its Sydney plant from 3.30pm on August 10 after the workers refused to cancel lawful industrial action during negotiations over pay and conditions.

Workers were directed to not attend or perform work until further notice and told they would not be paid during the indefinite lockout.

They have been picketing outside the site in Villawood and told Fairfax Media they were being "starved out" by the company. The company brought in labour-hire staff to take their place until the dispute is resolved.