President Park Geun-hye instructed Cabinet officials on Tuesday to beef up security at South Korea's main airport to ensure that safety breaches do not recur.

"Concerns have been raised about the security system in Incheon International Airport at a time when there is a growing terror threat," Park said in a Cabinet meeting, referring to a warning message found at the airport last week. The message, printed in Arabic on half an A4-size sheet of paper, read: "This is the last warning to you. God will punish."

The warning was found inside a box in a men's bathroom in the airport, though no explosives or detonators were found, according to the police.

Experts said there are some grammatical errors and the message is different from typical threatening messages, which either cite the Koran or are written in the name of Allah.

The airport has also been hit by a series of security breaches in recent months.

On Friday, a Vietnamese man illegally entered South Korea through the airport.

Police have yet to find the 25-year-old transfer passenger, who forced his way through the gate at an unmanned automatic immigration checkpoint in the airport.

Park also lashed out at lawmakers for their failure to pass an anti-terrorism bill, saying it showed they have no sense of urgency in protecting people's lives and security.

The anti-terrorism bill has gained fresh momentum in South Korea following the deadly attacks in Paris last year that killed 130 people.

Park also said the international community will call into question South Korea lawmakers if they fail to approve a bill meant to help improve North Korea's dismal human rights record.

The rival parties have failed to narrow their differences over the wording of a clause in the bill.

Similar bills were scrapped in recent years as liberal lawmakers have shied away from the issue of the North's human rights out of concern that it could harm inter-Korean relations.

North Korea has long been accused of human rights abuses, ranging from holding political prisoners in concentration camps to torture and carrying out public executions. (Yonhap)