Japan's defense minister says North Korea may be ready to carry out its seventh nuclear test.

Hamada Yasukazu was responding to a question by an opposition lawmaker at a foreign affairs and defense committee session of the Upper House on Thursday.

Hamada said his ministry will do its best to continue collecting and analyzing necessary information as well as surveillance in close coordination with the United States, South Korea and others.

The minister was asked by another opposition lawmaker about a delay in a nationwide emergency alert system to convey information on the North's launch of a ballistic missile that flew over Japan on October 4.

The policy chief of the Nippon Ishin Japan Innovation Party, Otokita Shun, said people have difficulty finding time to evacuate under the current J-ALERT system.

Otokita said many people are worried, and asked how the government intends to improve the system.

Hamada responded that it is extremely important to quickly and appropriately provide information to the people to safeguard their lives and property.

The minister said the entire government will continue to make efforts to ensure appropriate information transmission for the people.

North Korea has said a series of missile launches it has carried out since late last month were drills by its tactical nuclear operation units.

Japan's Foreign Minister Hayashi Yoshimasa said it was the first time for Pyongyang to mention such units.

Hayashi said the government will continue to do all it can to collect and analyze necessary information.