Nobel Laureate Aung San Suu Kyi has warned the US against being overly optimistic about Myanmar's chances of progress, saying political reforms in her country have stalled.

The Myanmar opposition leader's warning on Wednesday came a week ahead of US President Barack Obama's scheduled visit to the country for a regional summit.

Suu Kyi told reporters that she believed Washington and other powers were serious about wanting reforms, but said "there have been times when the United States government has been overly optimistic about the reform process".

"If they really study the situation in this country they would know that this reform process started stalling early last year," said the the 69-year-old democracy campaigner.

"In fact, I would like to challenge those who talk so much about the reform process, what significant reform steps have been taken within the last 24 months?"

Myanmar's military leaders moved to end the country's pariah status in 2011 by lifting restrictions on political opponents and releasing political prisoners, moves widely welcomed by Obama and the West.

But the government failed to curb tensions between majority Buddhists and Rohingya Muslims. Rights groups have also regularly accused the military of abuses and the authorities of cracking down on the media - at least 16 journalists have been arrested over the past year.

Suu Kyi is currently barred from running for president by Myanmar's military-drafted constitution which does not allow candidates with a foreign child or spouse. Suu Kyi's late husband was British, as are her two sons.

The military's significant presence in parliament allows it veto power over any attempt to amend the constitution.