Myanmar opposition leader Aung San Suu Kyi reached out to ethnic Chinese and minority voters Saturday on the campaign trail in the north of the country ahead of April 1 by-elections.

Addressing a crowd of about 20,000 people in the town of Lashio, which is near the border with China, Suu Kyi said some people were trying to stir up the Chinese community against her National League for Democracy (NLD).

"I heard that Chinese businessmen and merchants were threatened. They were threatened that their business could be harmed if our NLD won as we have very close relations with Western countries," she said.

"I would like to request the people to pass along the word that these things are not true," she told the crowd, who were holding banners reading: "People for Suu, Suu for the people" and even one in Chinese.

Many people in Lashio and the northern Shan state area are of Chinese origin, though holding Myanmar citizenship.

In her speech to the crowd, which included many Chinese and other ethnic minorities, she stressed that the NLD was not out to destroy Chinese businesses.

"We had good relations (between Myanmar and China) when we had democratic governments," she said, without specifying the period she was referring to.

"Problems were very few among us," she said.

"Both sides must have understanding to have fewer problems. What we want is mutual understanding. We will try to establish this kind of relationship (with China)," she said.

Lashio is a trading hub for Chinese goods such as clothes and electronics and many shops and houses have Chinese signs.

Myanmar's giant neighbour is its second-largest trading partner and biggest foreign investor and has helped shield it from international opprobrium and the impact of Western sanctions.

"We understand that investing and doing business in other countries is for our benefit," the Nobel laureate told the crowd.

"However the people in the host country should have benefited from it. The benefit should be for both sides," she said.

"We will work with this kind of spirit of equality."

Wearing a traditional Shan costume, she said the NLD was for all ethnic groups, not just the Burman majority.

Suu Kyi also warned the crowd to be on the lookout for vote rigging with just two weeks to go before polling.

"Frankly, we are seeing more irregularities are happening around the country. We have to be more careful at this juncture," said Suu Kyi, who has alleged that dead people are on the voter rolls.

She told people to inform the party of any cheating or threats so it could take legal action.

The NLD is contesting 47 seats out of 48 available in the by-elections.

The polls, which will see Suu Kyi stand for a seat in parliament for the first time in a constituency near Yangon, are viewed as a key test of the new government's commitment to reform.

The regime has so far impressed even sceptics with its reform process, which has included signing ceasefire deals with ethnic minority rebels and welcoming the NLD back into the political mainstream.