The union representing striking Belfast postal workers has denied it has rejected a proposal by Royal Mail to end the unofficial dispute.
Belfast postal workers' strike is continuing
The Communication Workers Union has been in talks with the Labour Relations Agency for four days.
Royal Mail claimed in a statement the union had rejected an offer to look at employee grievances only once they came back to work at the Tomb Street depot.
Union spokesman Peter Donaghy said Royal Mail had no firm proposals.
"Any firm proposals were put forward by us," he added.
"I'm not sure what the Royal Mail are saying: if they are saying they have put forward firm proposals, that's not true."
Royal Mail commercial manager David Peden said the company's position remained unchanged.
"We know that the people don't want to be out there: they are losing hundreds of pounds (and) their customers are in grave difficulty in many circumstances now," he said.
"They don't want that and neither do we.
"When they come back, we can talk about any legitimate concerns they have, but this action just cannot be carried on any longer."
Deliveries have been disrupted since more than 200 postal workers at the Tomb Street depot in Belfast began the unofficial strike on 31 January.
It followed difficulties between staff and management over disciplinary procedures and other issues in the north Belfast section.
It is understood the dispute relates to allegations of widespread bullying and harassment in the company.
However, Royal Mail rejected the claims, saying the company was only dealing with a small number of cases.
Post has been disrupted in north, south and west Belfast but an attempt to widen the strike to Londonderry failed because of a lack of support for the Belfast workers.
Royal Mail said customers needing more information and advice could contact its helpline number on 08457 740740.