A toxic gas leak Tuesday at a chemical factory in South Korea left 11 workers hospitalised and forced the evacuation of residents living nearby, local officials said.

The incident occurred at a factory in the southeastern industrial city of Gumi, where a hydrochloric acid leak at another factory last September left more than 3,000 people seeking medical treatment.

Tuesday's leak involved around one litre (around one quart) of chlorine gas and was contained within minutes, a city official told AFP, adding that it had been caused by a technical fault.

The factory was immediately evacuated, along with residents living close to the facility, while nearby roads were closed.

A total of 11 workers were taken to hospital complaining of difficulty breathing or eye irritation, a hospital spokeswoman said.

None appeared in serious condition and most would likely be released soon, she said.

The September acid leak had been far more extensive and resulted in the government designating the city a "special disaster zone" with widespread damage to crops and livestock.

Five people were killed in an initial explosion that led to the leak as workers were unloading hydrochloric acid from a tanker.