The average period for delivery of letters by Russian Post has increased from 12 to 15 days since 2009, the National Association of Distance Selling said in a report.
Only 37 percent of standard letters, as opposed to registered letters, are delivered within 10 days as compared to more than 70 percent four years ago, association president Alexander Ivanov told Vedomosti.
Government standards state that the delivery period of letters between Moscow and St. Petersburg must not exceed 11 days.
Ivanov placed blame for the delays on worn out transportation and outdated logistics systems.
The Association's report covers the period under the previous management of the state-owned mail service, which was replaced earlier this year because of the post's ineffectiveness. Besides delaying the correspondence of private individuals, the Federal Bailiff Service and leading phone operators like Rostelecom had complained of the late delivery of fines and bills.
The service was then put under direct control of the Communications and Press Ministry.
Deputy head of the ministry Mikhail Yevrayev told Vedomosti that ongoing modernization of Russian Post is expected to improve the speed of mail deliveries.
In late October, the service's new management stated an ambitious goal of doubling revenues to make the company ready for an initial public offering in 2018 by allowing it to provide banking services, reducing the number of unprofitable branches and focusing on providing deliveries from online retailers.