Translink has defended its decision not to use the Irish language on its main signage at the new Grand Central Station.

An Irish language group, An Dream Dearg, has criticised the move saying English and Irish dual-language signage has been excluded in what they called a “new multi-million monolingual monolith”.

Translink insists the new transport hub in Belfast will be ready to open on Sunday even though dozens of workers are still working on the site.

Bus services are due to begin on Sunday with the first departure – to Dublin – scheduled for 05:00 BST.

The new hub, Grand Central Station, is expected to cost about £340m.

There is still no date for the start of rail services but Translink insists it will be soon.

An Dream Dearg claimed the lack of Irish signage was against the wishes of the infrastructure minister, John O’Dowd of Sinn Féin, and Belfast City Council.

Speaking to BBC News NI, Ciaran Mac Giolla Bhein from An Dream Dearg said the group is “incredibly disappointed”.

When asked if the group will be taking legal action, Mr Mac Giolla Bhein said: “We may well find ourselves going down a legal route, but hopefully it can be resolved before that.”

“This is not just a transport hub for Belfast, it is a transport hub for people from right across the island of Ireland and it’s important that it’s reflective of where we are as a city,” he added.

Translink has defended its handling of the issue and said that Irish will be among the languages used on “multi-lingual welcome signage”.

There has been no comment yet from the minister who oversees public transport, Sinn Féin’s John O’Dowd.

On Wednesday, BBC News NI asked the Department for Infrastructure about the minister’s view on Translink’s decision, and whether or not he had the power to demand the use of dual-language signage.

In April, Belfast City Council approved a motion supporting “the installation of bilingual internal and external signage at Cros na bhFíodóirí – Weavers Cross – Belfast’s new Grand Central Station”.

In July, Translink’s chief executive Chris Conway wrote to the council saying that discussions were ongoing about signage with interest groups and political parties.

These included Conradh na Gaeilge and the Ulster Scots Agency, as well as the DUP and Sinn Féin.

Mr Conway indicated there was no consensus on the signage issue.

In terms of preparations for Sunday’s opening, the station’s manager Louise Doyle said “we’re nearly there”.

She added: “We just can’t wait to open the doors and welcome everybody in on Sunday with a big Belfast welcome.”

Ms Doyle has experience of building projects having worked at the new Wembley stadium in London and was also involved in the upgrade of Windsor Park stadium in Belfast.

She compared her work on Grand Central Station to a “baby that’s about to walk”.

“This is a huge infrastructure project that’s going to give back to the people of Belfast, Ireland and Northern Ireland for years and years to come.”

At a media preview of the new station on Wednesday morning, work was still going on inside and outside the station by workers in hard hats and hi-vis vests.

The sound of drills and hammering drowned out some interviews.

Translink chief executive Chris Conway thanked passengers for coping with the disruption to public transport services during recent months due to the switch to Grand Central as the new hub.

Asked when rail services would begin at Grand Central, he said a date would be announced “soon”.

A number of retail outlets are also planned for the new transport hub.