Chee Soon Juan has been imprisoned many times
The leader of a Singapore opposition party has posted a video message asking for US President Obama's support.
Chee Soon Juan, secretary general of the Singapore Democratic Party, posted his "message to President Obama" on the video sharing website YouTube.
Mr Chee said he hopes that the US "will pay more attention to the human rights abuses of the Singapore government".
Mr Chee has been jailed several times and faces multiple charges of defying local protest laws and other offences.
His Youtube message began with congratulations to Mr Obama, describing his inauguration as "an occasion of great moment".
He reminded the US president of his words on International Human Rights Day in December 2008, when he had aligned the US with "men and women around the world who struggle for the rights to speak their minds, choose their leaders and be treated with dignity and respect".
Mr Chee then spoke of the many men and women around Asia suffering in that struggle, notably Burmese opposition icon Aung San Suu Kyi, who remains under house arrest.
Mr Chee expressed the hope that with Mr Obama in charge, it could not be "repression as usual" in Burma, and that "urgent change must come" to the country ruled by a military junta.
In Singapore, Mr Chee claimed, repression was exercised through the "clever use" of terms such as rule of law and good governance "to cover up what is effectively a dictatorship".
"How else do we describe a government prohibits public speech and peaceful assembly controls media, detains citizens without trial and manipulates elections?" he said.
He expressed the hope that Mr Obama might "take positive steps to help Singapore join the community of democracies."
"Under your leadership I look forward to a world that is freer, more democratic and more just," said Mr Chee.
Mr Chee's YouTube message includes pictures apparently of poor Singaporeans living in cardboard boxes - an allusion to growing economic distress in a state that has made impressive economic success a key plank of its appeal at the ballot box.
The Singapore government has announced a new low in the level of economic performance expected this year - a contraction of between 2% and 5%.
Singapore President SR Nathan sent his own congratulatory message to Mr Obama in which he expressed the hope that the US would provide new economic leadership.
Mr Nathan noted the close ties between Singapore and the US which he described as longstanding, close, multifaceted and versatile.
The Straits Times newspaper in Singapore carried a brief report about Mr Chee's message without comment on Wednesday.
In the past the government has dismissed complaints about restrictions on freedom of speech and assembly as without substance.
A park is designated as a space for free speech in Singapore; outside that area, gatherings of more than five people need official permission.
Mr Chee is one of the few Singaporeans who have publicly spoken against Singapore's People's Action Party, which has ruled since 1959.
Singapore's leaders say tough laws against dissent and other political activity are necessary to ensure the stability which has helped the city-state achieve economic success.