Aung San Suu Kyi has urged foreign governments not to allow their companies form joint ventures with Burma's state-owned oil and gas company until it improves its business practices.
Ms Suu Kyi was speaking to the International Labour Organization in Geneva.
She is on her first visit to Europe in nearly 25 years. Until now, she was fearful that if she left Burma, the junta whose rule she fought against for two decades would block her return.
Burma has granted Chinese state-owned oil firm CNPC oil and gas pipeline concessions that will enable Middle East energy supplies to take a short-cut on the route to China, cutting out the extra expense and journey time of using the Malacca Strait.
"Quite frankly none of us know what's in those contracts, this is what I mean by lack of transparency in the country," Ms Suu Kyi said.
"Lack of transparency leads to all kinds of suspicions that shore up trouble for the future."
Asked about Chevron and Total, the big Western oil firms with investments in Burma, she said: "I have to say that I find that Total is a responsible investor in the country, even though there was a time when we did not think they should be encouraging the military regime by investing in Burma.
"They were sensitive to human rights and environmental issues and now that we've come to a point in time when we would like investors who are sensitive to such issues, I am certainly not going to persuade Chevron or Total to pull out."
A day after the UN agency lifted its more than decade-old restrictions on Burma in recognition of progress, Ms Suu Kyi received a standing ovation at the ILO's annual ministerial conference, where she said foreign direct investment that created jobs should be invited.
As sanctions are lifted, investment in the country should be responsible and add to, rather than subtract from, the process of democratisation, she said.
"The reason why we have to be careful about the extractive industries is because what you extract doesn't go back in, and secondly because they don't provide as many jobs as some other industries, so we want to approach this with caution.
"Burma is a land with a lot of energy resources. We do not want to dissipate it. I would like to see a sound effective energy policy in Burma and this should be related to the kind of extractive investments that we invite in."
She also said responsible foreign investment in agri-business could be beneficial, as long as the right precautions are taken to protect smallholders.
Her tour will include visits to Britain, Switzerland, France, Norway and Ireland.
When Ms Suu Kyi arrives in Dublin on Monday, she will meet Tánaiste Eamon Gilmore and President Michael D Higgins.
Later in the day she will be presented with an Amnesty International human rights award from U2's Bono.
She will also be given the Freedom of Dublin, which she was awarded while under detention in Burma, which is also known as Myanmar.
The European trip will also see Ms Suu Kyi accept her 1991 Nobel Peace Prize that thrust the pro-democracy movement into the global spotlight two decades ago.
The tour marks a new milestone in the political changes that have swept Burma since decades of military rule ended last year, bringing to power a new quasi-civilian government.
Ms Suu Kyi will now travel to the Swiss capital, Bern, to meet President Eveline Widmer-Schlumpf and Foreign Minister Didier Burkhalter.
Tomorrow, she will visit the Swiss parliament before heading for Oslo in Norway and later in the trip the veteran activist will address Britain's parliament.
The daughter of Burma's independence hero General Aung San won her first ever seat in parliament in April, prompting Western nations to start rolling back sanctions.