By Martin Nesirky and Lee Suwan

SEOUL, Mar 7 (Reuters) Give North Korea a Chinese-style emerging middle class and reforms will take care of themselves, former South Korean President Kim Dae-jung said today.

Kim also told foreign correspondents at his presidential library his postponed second trip to Pyongyang was likely to take place around June 15, the sixth anniversary of his unprecedented and unrepeated summit there with North Korean leader Kim Jong-il.

''There is no way to change communism,'' Kim said, noting Cuba had not yielded to US pressure for decades and urging South Korean firms to invest their unutilised capital in the North.

''If the country can make money, the economy will develop, a middle class will develop and people will voice their opinions,'' he said. This was what had happened in China, he said, where the economy was booming and the middle class was becoming increasingly influential.

The 82-year-old former South Korean leader won the Nobel Peace Prize in 2000 for his efforts to seek rapprochement with the communist North, still technically an enemy because the 1950-53 Korean War ended in a truce rather than a peace treaty.

Alongside family reunions and other exchanges, a key component in the process since his summit with Kim Jong-il has been work to relink railways through the heavily fortified Demilitarised Zone that bisects the peninsula.

So far, North Korea's powerful military has been reluctant to open the railway the route Kim Dae-jung would like to take when he visits Pyongyang as a symbol of his wish for ''Iron Silk Roads'' to reach as far as Europe through China and Russia.

''If North Korea sets its mind to it, it can happen any time,'' said Kim, who was in hospital twice last year but has recovered although he suffers kidney problems and has some trouble walking.

If the railway worked properly and South Korea coupled its capital and know-how to North Korea's labour and land, the North could grow and the South would avoid high unification costs, he said.

''It would be an age of prosperity we cannot even imagine,'' Kim said. ''The fact the two Koreas are divided would have little meaning.'' A South Korean-funded industrial park in Kaesong, just over the border in the North, was an early taste of that, he said.

Some critics have said overseas investment in North Korea only helps to support the North's leaders and prolongs their authoritarian rule over the country.

Kim who was president from 1998 to 2003 -- said North Korean attitudes toward South Koreans had changed greatly and they now even envied those in the South.

Kim diplomatically ducked a question on South Korean President Roh Moo-hyun's administration, saying he did not know much about domestic politics these days. But he did suggest Roh should visit the North.

It was not clear why Kim Jong-il had not made his promised reciprocal trip to the South, the former president said.

''Chairman Kim owes me one,'' he said. ''He said he would visit but did not.'' REUTERS SY BS1621