The monk, who was not identified by name, told the radio station: "We walked around the town and chanted. ... We are continuing our protest from last month as we have not yet achieved any of the demands we asked for."
"Our demands are for lower commodity prices, national reconciliation and immediate release of (pro-democracy leader) Aung San Suu Kyi and all the political prisoners," the monk said.
He said they had little time to organise the march so it was small, but "there will be more organised and bigger protests soon".
Earlier, the government released seven National League for Democracy (NLD) party leaders after detaining them for more than a month following the bloody crackdown on anti-government protests.
Nyan Win, a party spokesman, said Myint Thein, Han Zaw, Lei Lei, Ko Bala, Cin Shin Htan, Htaung Ko Htan and Win Naing were detained at the Insein Prison in Yangon.
The move came in advance of Saturday's visit by the special UN envoy, the said on Wednesday.
Ibrahim Gambari, the UN secretary-general's envoy to Myanmar, is due for a second visit to seek reconciliation between the ruling generals and the opposition led by Aung San Suu Kyi.
Aung Zaw, the editor of Irrawaddy
, a magazine run by exiled journalists based in Thailand, told Al Jazeera that accordind to the monks he has spoken with, the protests are a continuation of a religious boycott, and is clearly in defiance of the military government.
He said: "I was told that at least 150 monks were involved in the protest."
Han Tha, another spokesman, told The Associated Press news agency that the NLD demanded the "immediate and unconditional release of all those detained arbitrarily".
He said at least 150 party members were still in detention out of nearly 300 arrested since September, and many were denied proper medical treatment and lived in harsh conditions.
In recent weeks, human-rights reports have emerged detailing accounts of brutal treatment in custody, claims Myanmar's military government denies.
The government said it arrested about 3,000 protesters but had already released most of them.
Protests over higher fuel prices that began on August 19 turned into massive anti-government demonstrations weeks later in the biggest show of dissent in almost 20 years.