Gmail users have been reporting in droves that the Google webmail service is resending messages to their recipients, turning these users into accidental spammers who are unintentionally annoying friends, acquaintances and business contacts.

Starting on Tuesday, users have filled multiple pages of the official Gmail Help Forum with complaints about this problem, which is causing them and their recipients grief.

In this thread, a Google employee identified as MrEvan popped in to say the company is looking into the issue.

"Thanks for your reports. Just wanted to let you know that the engineers have been working on this. I should have more details tomorrow about what's going on, what you can expect, and progress toward fixing this for you asap," Mr Evan wrote in his message, posted at around 1 am US Eastern Time on Wednesday.

Google didn't immediately respond to a request for comment.

"Three recipients of my Gmail messages sent using Firefox have complained that they are receiving the same message 3-4 times over. And they want me to do something about it! Gmail, please help as these are important business clients," wrote one user in the thread.

A scan of the complaints reveals that affected users are using a variety of operating systems, browsers and e-mail client software. The problem seems to have started several days ago, but affected Gmail users mostly began reporting it on Tuesday.

The problem apparently happens with some messages and affects some recipients, but when it strikes, it creates a difficult and embarrassing situation for senders, who ultimately aren't at fault and can't solve the issue.

Some of the affected messages are re-sent over a period of days.

Currently, a majority of the threads in the first seven pages of the "Composing and Sending Messages" section of the Gmail Help Forum are about this problem.