South Korean President Lee Myung-bak is visiting Burma, the first time a South Korean leader has visited the country since a bomb attack 29 years ago.
The North Korean attack, during a visit by former President Chun Doo-hwan to Rangoon in 1983, killed 21 people.
Mr Lee met Burma's President Thein Sein in the capital Nay Pyi Taw on Monday as part of a two-day visit to discuss economic co-operation, officials said.
He is due to meet opposition leader Aung San Suu Kyi in Rangoon on Tuesday.
Details for the trip were kept secret due to security concerns in the wake of strong North Korean rhetoric against Mr Lee, officials said.
Mr Lee travelled to Burma from Beijing, where he had met the Chinese and Japanese leaders for two days of trilateral talks.
Tensions with North Korea following a failed rocket launch last month were discussed at the annual three-way summit on Sunday. But there was no mention of North Korea in a joint statement issued on Monday.
The meeting in the Chinese capital came amid speculation that Pyongyang may be planning a third nuclear test.
Mr Lee is the latest in a series of world leaders and diplomats to visit Burma as it continues to introduce political reform following the transition from military to civilian rule.
South Korea is keen to expand its economic ties in the region, says the BBC's Lucy Williamson in Seoul, but officials say the trip is more important for its diplomatic significance.
Seventeen South Korean officials - including cabinet members and members of parliament - and four Burmese people were killed in the 1983 attack as they waited for Mr Chun to visit the Martyrs' Mausoleum in Rangoon.
Mr Chun narrowly missed the attack as his car was stuck in traffic, causing him to be late for the event to lay a wreath for Burma's independence hero, General Aung San.
Three North Korean suspects were identified - one died while being arrested. Of the other two, one confessed and was jailed for life, while the other was hanged.
Burma cut diplomatic ties with North Korea in 1983 but resumed them in 2007.
Although Mr Lee is expected to focus on trade ties, political watchers suggest that he could also broach the issue of Burma's military links with North Korea.
South Korean officials have expressed concern that Burma could be working with the North to develop nuclear missiles.
In Rangoon, Mr Lee is expected to visit the mausoleum and meet General Aung San's daughter, the pro-democracy leader of the National League for Democracy (NLD), Aung San Suu Kyi.
Ms Suu Kyi led her party to win 43 seats in parliament in a by-election last month.
Security has been stepped up in the city, with increased police presence especially around the shrine where the attack took place in 1983.