North Korea will accept any South Korean delegations that want to express condolences in Pyongyang for the death of leader Kim Jong-Il, the North's official website said in a posting seen Friday.

"A wide variety of people in South Korea are eagerly asking for a visit to express condolences," said the Uriminzokkiri website in a post dated Thursday.

It said the North would "respectfully accept all types of South Korean delegations hoping to visit to express condolences and they have taken steps to open all air routes, and land routes through (the border town of) Kaesong".

Uriminzokkiri said the safety of South Korean visitors would be guaranteed.

"This is a sign of our courtesy and respect for the warm heart of South Koreans who wish to share the sorrow of our biggest national mourning."

The South's government, in a conciliatory move at a time of high tensions, expressed sympathy this week to the North's people following Kim's death last Saturday.

But the Seoul government, which must by law authorise all contacts between South and North Koreans, has said it will permit only two delegations to attend the late leader's funeral next Wednesday.

The North's latest announcement appeared to be a move to wrong-foot it.

Uriminzokkiri criticised the decision and accused Seoul of trying to escalate confrontation through its talk of a military alert.

"These are intolerable actions mocking and insulting our dignity," it said.

"The South Korean government's action in banning... visits to express condolences is an unacceptable and uncivilised action against humanity," the website said, adding it could have a "significant impact" on relations.

Uriminzokkiri also called on the Seoul government to "show necessary actions of respect".

It added: "We will keep in mind those who do not understand even the most basic actions of respect and humanity and who insult our dignity, and we will make them pay a very expensive price for that for years to come."

Seoul said Tuesday it would not send a government mourning delegation to Pyongyang. But it would allow the families of South Korea's late President Kim Dae-Jung and of former Hyundai group chairman Chung Mong-Hun to attend the funeral.

Kim Dae-Jung and Kim Jong-Il held the first-ever North-South summit in 2000 and the Hyundai Group pioneered cross-border business exchanges.

The North has said it would not host foreign delegates at the funeral but South Koreans are not considered to be foreigners. (AFP)