The country's two largest mobile service providers, MobiFone and VinaPhone, will cut charges on August 10 after a delay of more than a week.

The Viet Nam Post and Telecommunications Group, which owns both, gave its consent for the cuts on July 30 while the plans have been bandied around for several months, meaning they should have been better prepared to implement the cuts, critics said.

In the past tariff changes have never taken this long to effect, they pointed out.

The military-owned Viettel announced rate cuts of 10-15 percent – or 100-200 VND per minute – on July 27 and effected them the same day.

The delay has benefited MobiFone and VinaPhone, which promised to cut tariffs by 10-15 percent, to the extent of billions of dong.

The two have around 72 million subscribers. Assuming each makes a two-minute call daily, at the rate of 1,000 VND a minute the companies' daily revenue is 14.4 billion VND (758,000 USD).

The two companies explained the delay by saying they need time to adjust the systems.

They are also promising to make up to subscribers by offering freebies.

A VinaPhone spokesperson said pre-paid customers will get a 100 percent bonus while post-paid subscribers will get free calls and SMSs.

"VinaPhone will announce the promotion next week," he said.

A MobiFone spokesperson also promised special promotions, including extending the "call 10 minutes pay for one" promotion by a month to the end of September.

VinaPhone is set to cut call charges by an average of 11.21 percent.

The country's other service providers, S-Fone, Vietnamobile, EVN Telecom, and Beeline have showed no signs of joining the race to the bottom./.