A court in Myanmar has delayed the trial of Aung San Suu Kyi, the detained pro-democracy leader for at least two weeks, her lawyer says.

The Yangon District Court on Friday pushed back until June 26 the date to hear the charges against Suu Kyi and John Yettaw, a US citizen whose uninvited visit to her home last month was deemed a breach of her house arrest.

Suu Kyi's lawyers asked for an adjournment to allow Khin Moe Moe, a legal expert and the defence's only remaining witness, to testify at the trial.

"We requested the further adjournment since Daw Khin Moe Moe has to come here from southern Shan State," Nyan Win, part of Suu Kyi's legal team, said.

Suu Kyi faces up to five years in prison if found guilty of violating her house arrest after Yettaw, swam across Inya lake and stayed for two nights at her Yangon home.

Trial criticised

Critics say the trial is politically motivated to keep Suu Kyi in detention during next year's elections.

A conviction for the Nobel laureate, who leads the National League for Democracy (NLD) party, is widely expected.

The Supreme Court on Thursday accepted an appeal over a lower court's decision to bar two of her defence witnesses, Win Tin, a senior NLD member, and Tin Oo, the party's detained vice-chairman.

An appeal will be heard on June 17 and if the court overturns the bans and allows the pair to testify, a verdict on Suu Kyi's case would likely take longer.

Nyan Win said Khin Moe Moe's testimony would highlight flaws in the prosecution's case and "explain that these charges are all politically motivated".

Archaic law

Suu Kyi is charged under Section 22 of an internal security law to protect the state from "subversive elements", but her lawyers say all charges should be dropped because the legislation is outdated.

The defence team blamed lax security for allowing Yettaw, who said he was sent "by God" to protect Aung San Suu Kyi from "terrorists", to swim to her home.

Suu Kyi has spent more than 13 years in detention since her first period of house arrest in July 1989.

Her latest stint was lifted on May 26 and she is now being held at Yangon's Insein prison while the trial, which has sparked outrage around the world, continues.

Western governments and Myanmar's neighbours have urged the country's military rulers to free Suu Kyi, and other political prisoners, to allow them to take part in next year's polls.