Despite the management lifting the lockout at its plant on Monday, Toyota workers refused to sign a code of conduct and did not return to work.
"About 500 workers gathered outside the plant to resume their work. However, the management insisted on signing some documents which had a code of conduct," Prasanna Kumar, president, Toyota Kirloskar Motor Union.
Kumar said the undertaking is against their right as workers.
"We have to think about ourselves. We cannot afford to put our right on stake," he said.
The union also demanded to reverse their decision to suspend 17 workers. No company officials were immediately available for comment. But Kumar said the union had asked the state government "to direct the company to lift the lockout unconditionally", claiming the shutdown was illegal as it was declared without a statutory two-week notice period.
Even on Saturday, the union had said they will not sign any undertaking.
The union alleged that the management is exploiting the workers by following unfair labour practices.
Toyota said it will keep the plants open for team members to join duty on the condition that they would sign good conduct undertaking.
"The company will welcome any steps that the Karnataka government can take to resolve the matter at the earliest," a company statement said.