Bewley's cafe on Grafton Street, which has been one of Dublin's most popular institutions since it opened in 1927, is to close soon for at least six months for a major refurbishment. The café's 140 staff will be made redundant.

When it reopens in the autumn, the cafe will be smaller and have a smaller menu.

Bewley's chief executive John Cahill said the operation needed to be simplified to put the business on a sustainable footing. "We have a choice of either permanent closure or investing in a realignment and rejuvenation of the cafe," he said. "We have chosen to underpin its future sustainability through a restructuring plan involving further investment and improvement."

Mr Cahill said it was “deeply regrettable” this would result in redundancies.

Bewley’s plans to shut the cafe next month and reopen in September. It will spend more than €1 million on an upgrade of the protected structure.

In a bid to reduce annual losses of €1.2 million, the company has decided to trade only on the ground floor of the 18,000sq ft premises after it reopens. This will roughly halve its seating capacity to about 160. Opening hours will be reduced and there will be just 70 employees.

The cafe will have a new menu and Bewley’s intends to focus on serving hot drinks, baked items and cakes rather than hot food.

Bewley's has fought an unsuccessful campaign with its landlord Ickendel Ltd, which is controlled by property developer Johnny Ronan, to have its €1.5 million annual rent reduced to €728,000, which was suggested by a third-party arbitrator in January 2012.