More mail misery is in the pipeline after union leaders urged Oxfordshire postal workers to vote for strike action.

The head of the local Communication Workers Union paved the way for further disruption when a national ballot opens next Wednesday.

It comes as the battle continued to sort thousands of items of post which have built up from recent stoppages caused by strike action at the region’s main sorting depot in Swindon.

Paul Garraway, CWU Oxfordshire branch secretary, said: “I am urging my membership to vote ‘yes’ for strike action in the national ballot.”

The union is looking to strike a deal over working conditions with Royal Mail, which is pushing ahead with a company modernisation programme.

The battle cry also came as it was disclosed the Oxford mail centre had been reopened in a bid to handle the mountain of letters and parcels built up by continuing strike action.

The base in Garsington Road, Cowley, closed in June as Royal Mail shifted its main operation to Wiltshire, with hundreds made redundant.

But management have been forced to reopen the building to deal with mountains of unsorted post.

Neither the company or the union could say last night how many items had been delayed by the action.

Mr Garraway said few of his union members had stepped forward to clear the backlog and managers helped with the sorting operation.

He added: “I shall be instructing my members not to touch strike mail in exchange for overtime or to work in the mail centre.”

Royal Mail spokesman Jacquie Stenson said: “We have contingency arrangements in place, including the use of managers to minimise the impact of the industrial action and to return service to normal as quickly as possible.

“We are again urging the CWU to stop hurting customers and to call off their strikes.

“The Oxford mail centre was used on one occasion to sort mail — that was last Sunday.

“We are using all the resources at our disposal in order to restore normal service for our customers as quickly as possible but there are no plans to open it again this weekend.”

The Royal Mail announced two years ago it was closing the Oxford mail centre and shifting the sorting operation to Swindon under a £90m reorganisation, which also involved the closure of the Reading sorting office.

The CWU saw it as an attempt to break the union.

The transition has not been smooth, with Swindon mail centre staff striking for 24 hours earlier this month, while a 48-hour stoppage by lorry drivers bringing mail back to Oxford caused a further backlog.

The union is demanding more “family friendly” working hours, clear working terms and conditions and an end to alleged bullying and harassment of staff.

Since its closure, the Oxford centre, which is leased by the Royal Mail, has been on the market but no deal has been signed with a new occupier.