British Broadcasting Corporation
Postbox Earlier strikes caused a backlog of 35 million letters, Royal Mail said.
A third round of postal strikes may be avoided, union sources have told the BBC.
The sources said a possible deal was on the table. Royal Mail is not commenting on the speculation.
The latest planned industrial action, scheduled for Friday and Monday, would be more disruptive than previous rounds as it would be an all-out strike.
At the heart of the dispute is union concerns over the extent of job cuts, and conditions for staff who remain.
Thursday's meeting includes the Communication Workers Union's (CWU's) Postal Executive - the union body that has the power to call off strikes. A statement is expected later.
'Period of calm'
The BBC's Greg Wood is at the TUC headquarters where the talks are taking place. He said that even if the strike is called off, it does not mean that the dispute has been resolved.
Instead it would amount to "a framework for proper talks, instituting a period of calm during which they can take place".
Postal expert David Stubbs, from Europe Economics, said: "An agreement on a national level does not necessarily mean an agreement on a local level...and that could sow the seeds for a future dispute."
He said that one of the issues was the relationship of unions at national level and its members at local level.
Royal Mail is trying to modernise to compensate for letter volumes dropping by 10% every year as people switch to other forms of communication such as e-mails and texts.
It has shed 63,000 frontline postal staff in recent years, and says it needs to cut more jobs as part of continuing modernisation plans.
The CWU agrees that job cuts are necessary, but disagrees over their extent, and over the future pay and working conditions of the workers that continue to be employed.
Delays
There is still a three million letter backlog from last week's strikes, half of which are in London, according to Royal Mail.
In total it estimated that the action caused 35 million letters to be delayed. Unions claimed the figure was nearer to 60 million.
If the talks are unsuccessful, the CWU will go to court on Friday to try to prevent the Royal Mail from using agency workers during the industrial action.
Royal Mail has denied that employing the 30,000 extra staff is an attempt to break the strike, but instead to deal with the backlog and the Christmas rush.
Are you a postal worker? Have you been affected by the strike action so far? What do you think of the latest news? You can send us your experiences and views using the form below:
The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.
Terms & Conditions
Print Sponsor
Royal Mail stamps
Changing marketMark Higson
Royal Mail on strike call offDave Ward
CWU on mail strike call offStriking postal worker
On the picket line: Striking postal workers speakProtesting businessman
Businessman challenges the picket linePicket line in Wales
How the strike is affecting different parts of the UKvideo Army 'dissent' over West Bank role
video Living the American dream
video One-minute World News
video Susan Boyle is mobbed in New York
video How SA's poor get free electricity
video Death toll rises in Philippines
video Queen and Duke arrive in Bermuda
video Obama to 'finish job' in Afghanistan
video 'Zionism succeeded to create an Israeli nation'
video Widow's tribute to army bomb victim
Chimneys silhouetted against the sun
Warming globeUS President Barack Obama and Commander of US Forces in Afghanistan Stanley McChrystal
Mardell's AmericaA man in the act of killing a buffalo
In picturesMost Popular Now | 16,057 people are reading stories on the site right now.
Quantcast
BBC © MMIX
The BBC is not responsible for the content of external internet sites.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.watch One-Minute World News