"Na's remarks amount to an insult to the head of state and the public who aspire for peace on the Korean Peninsula," the office said.

The presidential office expressed hope that Na's remarks did not intend to bring Cold War animosity back to the peninsula.

"(The LKP) should not waste energy that should be spent for the nation in insulting the people and the head of state. The LKP and Na should apologize to the people who aspire for complete denuclearization and permanent peace," it added.

Na's remarks have sparked political tension at a time when an extra parliamentary session just kicked off last week following a two-month hiatus.

The ruling Democratic Party vehemently denounced Na at a hastily arranged general meeting of party lawmakers.

"I think Na's remarks cannot be acceptable politically. It is an insult to the head of the state," DP chairman Lee Hae-chan told the meeting.

"Our party should immediately review the filing of a petition with the parliamentary ethics committee and draw up measures to prevent a recurrence," he added.

Minor opposition parties also criticized Na's speech.

"Na's remarks are nothing but vulgar criticism," the conservative Bareunmirae Party said.

"It is a comedy in that the LKP likened Moon to a spokesman for Kim Jong-un, and it revealed its plan to send a special envoy to the North at the same time. This absurd speech does not help North Korea's denuclearization nor improve inter-Korean ties," it added.

At the main chamber of the National Assembly, Na had to stop reading her speech amid strong protest from DP members. Ruling and opposition lawmakers exchanged inflammatory remarks and screamed at each other with some involved in a scuffle.

"DP lawmakers who were hell-bent on currying favor with Cheong Wa Dae did not hesitate to make senseless acts to deter the main opposition floor leader's speech," the LKP said.

The LKP is already at odds against the DP and three minor parties over whether to fast-track an electoral reform bill.

Despite the LKP's objection, the DP and smaller rivals seek to fast-track a revised election law that includes the adoption of a new proportional representation system. (Yonhap)