A former South Korean foreign minister on Wednesday advised Seoul and Washington to bring North Korea out to negotiate its denuclearization before the allies' annual joint military exercise slated for March next year raises tensions with the communist state.

"I think the time must be before March if (the allies) intend to bring North Korea to the negotiating table to strike a deal," Yoon Young-kwan, who served as the foreign minister from 2003-2004, said at a local lecture.

"There are growing forecasts that North Korea may take about one year to integrate an intercontinental ballistic missile and a miniaturized nuclear warhead and deploy it," Yoon said. "This means the deadline is approaching for US President Donald Trump."

Against this backdrop, the beginning of the regular joint military drill between South Korea and the US in March is sure to escalate tensions on the peninsula, he noted, saying "This is why I stress the time before March would be very important."

The former minister suggested a freeze of North Korea's nuclear program as the "most realistically viable" option to achieve a breakthrough in the current stalemate involving North Korea's on-going development of nuclear weapons.

"First of all, the US could propose North Korea suspend its nuclear tests and long-range missile tests and then move on to demand it suspend nuclear activities at the Yongbyon (nuclear complex). In return, North Korea may be able to demand the termination of joint South Korea-US military exercises and sanctions as well as a signing of a peace regime," according to Yoon.

He also called the recent war of words between Trump and North Korean leader Kim Jong-un "a very bad sign" which, he said, boxes them into a corner in which they must choose to act as they said or be called a coward. "One needs to extremely refine its message to send and send a coherent message."

"What I suggest is that the US consistently sends out a message to North Korea that 'what we want is not a regime change or a preventive war, but a policy change toward your denuclearization,’" Yoon said.

Also drawing on South Korea-China relations, the former minister said the countries have not facilitated strategic cooperation on the North Korean issue despite success in social, cultural and political cooperation.

"The biggest goal for South Korea-China relations is to resolve the North Korean issue ... I think they can share and properly cooperate on the point South Korea wants denuclearization of North Korea, not its collapse," he said. (Yonhap)