HANOI (Reuters) - Vietnam’s government has promised a full review of charges at a toll gate on a new road after protests there posed a rare challenge to the Communist authorities and showed signs of spreading.

Charges at the Cai Lay toll road in southern Vietnam were suspended by the government on Monday after protesting drivers caused long tailbacks by paying fees in bundles of tiny denomination bills.

There is little tolerance of dissent in Vietnam and the government is acutely sensitive to any sign of public disaffection, particularly if it spreads on social media.

In comments published on the government’s website on Friday, Transport Minister Nguyen Van The said he was investigating alternative proposals for operating the toll road.

“We will carry out our research and complete the report to the government,” he was quoted as saying. “Whichever option we choose for Cai Lay will have an impact on other BOT (Build Operate and Transfer) projects.”

He dismissed accusations on social media that officials had benefited from connections to the company operating the toll gate. Vietnam is also in the midst of a crackdown on corruption.

There are some 88 toll stations on Vietnamese roads set up by investors under BOT schemes to finance construction.

But the one on the Cai Lay toll road caused anger when it opened in Aug. 1, because its location meant even drivers who were not going to use the new road had to pay. The investor said that was fair because it had also repaired the old road, but drivers pointed out those repairs cost very little.

Charges were suspended when protests started after the toll gate first opened, but the toll booths reopened on Nov. 30.

To protest, some drivers paid tolls of 25,000 ($1.10) to 140,000 dong using low-value notes – sometimes requiring the toll gates to count hundreds of bills for a single transaction.

Similar protests then appeared on roads in other parts of the country, causing long hold-ups for traffic in one of Southeast Asia’s fastest growing economies.

Authorities needed handle the situation sensitively, said one Facebook user, who commented: “This could become a bigger problem if they shield each other against this legitimate protest by the people”.

The toll gate protest is one of the biggest public displays of anger in Vietnam since demonstrations in 2016 against a toxic spill from a steel plant and the slow government response to the marine environmental disaster it caused.

The Vietnamese company that built the new road, National Highway No. 1 Tien Gang Investment Co. Ltd., told media that unhappy road users should understand that it was a business with workers and their families to support.