Small businesses are under threat and jobs will be lost if postal services in Belfast are crippled by a second strike, it was claimed tonight.
The Communication Workers Union is considering balloting its members on industrial action less than a week after the 18-day dispute was called off.
Shop stewards have claimed staff who took part in the unofficial action have been victimised since they returned to work.
But Royal Mail denied the allegations and branded the union irresponsible.
The Federation of Small Businesses said its members were still suffering from the mammoth backlog left by the strike, while the Ulster Unionist Party urged the British government to get involved before the dispute escalates.
Harry McGimpsey, FSB Branch Chairman, said: “The bottom line is this – if there is another sustained postal strike, then we will see many small businesses close with widespread job losses, which can cause severe damage to our local economy.
“Both sides in this dispute must resolve their differences and find a lasting agreement, which will put an end to any prospect of a new strike.”
John Farnan, of the CWU’s national executive, said by Wednesday both parties expected to agree the identity of the body which will carry out an independent review of industrial relations at the Belfast depot.
But he said the issue of discrimination remained a sticking point and will be the focal point of further talks.
Mr Farnan said: “What has been happening is that people who did not take part in the strike have been treated more favourably.
“We are hoping that might be eliminated on Friday but if it is not then the ballot will still go ahead.”
Following talks in a city centre hotel the CWU official said progress had been made.
On the prospect of a second strike, Mr Farnan said: “We would like to allay that fear.
“The public have been very supportive and we want to support them and do everything to alleviate the need for industrial action.”
Royal Mail said it was optimistic an agreement would be reached.
A company spokeswoman said: “It was a constructive meeting and we have made good progress on selecting a third party to look at employee and industrial relations within Royal Mail in Belfast.
“Both parties are equally resolved to moving forward.”
Earlier the Director of Personnel for Royal Mail in Northern Ireland said the company was focused on clearing the backlog.
Gary Crawford said: “We’re really not quite sure what the grounds for a strike ballot are because our decision to employ temporary staff rather than create the opportunity for excessive levels of overtime is a standard industry-wide practice.
“To attempt to further undermine customer confidence by threatening either official or unofficial action, out of pure self interest, is just the irresponsible actions of a few.”
UUP leader Sir Reg Empey tonight urged the Northern Ireland Office to intervene in the dispute before it escalates further.
Mr Empey said: “The possibility of an official strike is a major concern.
“The previous strike has affected our economy and is still causing huge disruption in our health service and other public services.
“Angela Smith (enterprise minister) needs to intervene before this situation develops further.”
Royal Mail last week said it will take up to a month to clear seven million letters and parcels delayed by the strike.
Extra staff have been hired and other distribution centres across the UK are being used to help shift the massive backlog.
The unofficial action began on January 31 amid allegations of management harassment and bullying at a Belfast depot.