Thailand's military government is evicting thousands of much-loved street-food vendors from their usual spots in a bid to clear walkways and bring order to the capital.

The move has been criticised for depriving people of affordable meals and pushing Bangkok towards a more sterile future.

"The street food of Bangkok is the blood of Bangkok … this is the charm, it is the fame, it is the identity of Bangkok," said Korakot Punlopruksa, a food writer and travel show host.

"I think it's a little bit short-sighted for the Bangkok authority to do this to all the life in Bangkok."

Food writer Korakot Punlopruksa says authorities don't understand that street food is the "blood of Bangkok". ( ABC News: Liam Cochrane )

CNN recently ranked the city as having the world's best street food for a second year in row, with Sydney placing 22nd.

The soldiers who run Thailand, following a 2014 coup, welcomed the praise.

"Prime Minister (General Prayut Chan-o-cha) knew about this and he is glad that Bangkok was still chosen as the world number one for street food," Government spokesman Lieutenant-General Sansern Kaewkamnerd said.

But even as the accolades were being accepted, the Bangkok Metropolitan Administration was handing out eviction notices in some of the most popular street-food hotspots.

Sellers on Thonglor, Ekkamai and Pridi Banomyong roads have until April 17 to cease operations.

"They told us there were complaints that we blocked the footpath," said 51-year-old Malai Panuwannarat, who sells noodle soup on Thonglor Road.

"We've been here for 17 years … but we have to accept it."

Malai Panuwannarat will be evicted in weeks. ( ABC News: Liam Cochrane )

Nearby, on Soi 38, three generations of women had sold rice with pork leg on the street until being forced into a carpark late last year.

"I took over from my mum when she was retired at 63 years old," Bangurn Meebuaheng said, as she and her daughter prepared for the evening's diminished trade.

"When we were outside everyone can see us [and] we got both regular customers and those just passing by … but since we moved in here our income dropped so much."

Soi 38 was previously a mecca for visiting foodies, locals and expatriates living in the fashionable Thonglor district.

"There were a lot of foreigner customers before, they came back and showed me old pictures and asked where have were all vendors gone," Ms Bangurn told the ABC.

Three generations of Bangurn Meebuaheng's family have sold rice with pork leg on Soi 38. ( ABC News: Liam Cochrane )

The Bangkok Metropolitan Administration declined a request for an interview, saying it was too busy to provide details about the clearance operation.

Local media reported 15,000 street-food vendors had been handed eviction notices.

While congestion is a problem on the streets of Bangkok, some areas are being developed with luxury condominium buildings and high-end retail.

Most of the food sellers will take their carts and plastic chairs, and try to find new locations on smaller lanes.

"I will go and find them [when they relocate] but I think from their business point of view, losing the frontage of Soi Thonglor is going to probably be quite hard for them," British expatriate Adam Spacey said, as he ate a rice dish at a soon-to-close stall.

Adam Spacey says he will follow his favourite stall to its new location. ( ABC News: Liam Cochrane )

"This is just a nice place to have a snack, it's also very, very wholesome food at a very affordable price," Mr Spacey said.

Many Thais rely on street food for a nutritious meal costing only $1 to $2.

One study estimated that two-thirds of Bangokians eat at least one meal a day from street-side vendors.

"I usually come to eat here — I don't go anywhere else, always this one," Anatchaya Chaisanam, a motorbike taxi rider eating a lunch of chicken noodle soup, said.

"If there are only expensive places, people who have same job as me, just can't afford it."

Street food is a crucial part of daily life for the city's low income workers, like motorcycle taxi Anatchaya Chaisanam. ( ABC News: Liam Cochrane )

In a hierarchical culture of vast wealth gaps, street food is a great leveller.

"Bangkok has so many layers, complexities of life, super-poor to super rich … [but the] authorities don't understand what is the identity of Bangkok," Ms Korakot said.