Six senior members of the National Federation of SubPostmasters (NFSP) have been suspended for voicing opposition to proposed changes to the Post Office network.

The national vice-president, the South East and South West regional presidents and secretaries endorsed a letter sent to all NFSP members, calling for action on the Post Office Local proposal, which they believe will cause a 75% fall in subpostmaster salaries and result in more branch closures.

Post Office Local is a new service model currently being trialled, which allows subpostmasters to offer limited services over the counter rather than at a dedicated PO counter. The suspended executives believe it will be made compulsory and that 6,000 branches would be forced to stop providing other Post Office services. They have called for an amendment to the Postal Services Bill that allows subpostmasters an equal say in the running of the Post Office network.

But NFSP general secretary George Thomson said the letter was "scare-mongering" and did nothing to help subpostmasters. "The negotiations for Post Office Local are still ongoing and it is our ambition that it will be a voluntary scheme," he said. "We will do our utmost to ensure that subpostmasters have a choice on Post Office Local. The people who sent out this letter do not speak for the NFSP."

In a statement on the South East Regional Council website, www.actionchange.org,uk, the group said that it was not its intention to "split the Federation or humiliate any colleagues" and that "due to the actions of certain key members of the executive, they were forced to take necessary action that was in the best interest of all postmasters".

It claims that it has received enough letters of support to call a special conference of the Federation.