
"This convoy marks a positive step in an aid effort so far marked by challenges and constraints," said Raymond Hall, UNHCR's Representative in Thailand.
"We hope it opens up a possible corridor to allow more international aid to reach the cyclone victims."
Hall added: "What we are sending in by road is in addition to the supplies we have already procured locally in Yangon and the 100 tons of supplies we started airlifting today from Dubai."
UNHCR has also started airlifting 100 tons of shelter supplies, including 4,500 plastic sheets and 17,000 blankets, from its Dubai stockpile to Yangon early Saturday.
The first 33 tons left on a World Food Programme aircraft with two other flights scheduled for early next week.
The refugee agency is focusing on providing emergency shelter for the cyclone victims in the Irrawaddy delta and parts of Yangon, which were among the worst hit. More than one million people are estimated to have lost their homes after Cyclone Nargis hit last Friday.
UNHCR has already distributed 50,000 dollars worth of shelter items bought locally in the aftermath of the storm.
The lorry convoy is expected to take around two days from the border to Rangoon in the south. The supplies, raided by UNHCR from its existing stockpiles normally intended for refugee camps scattered along the Thai-Myanmar border, will be distributed by UNHCR staff.
UNHCR negotiated a concession for the border posts to stay open at the weekend to allow the convoys through.
UNHCR launched a 187 million dollars appeal for Burma Friday which included six million to provide 250,000 cyclone victims with shelter.