Domino's Pizza has said that its sales in Ireland grew by 5.1% to €12.1m in the 13 weeks to the end of June.

It also reported its sixth month in a row of positive like-for-like sales growth, leading to growing confidence that the Irish market is now ''heading into clearer waters''.

Domino's has 48 Irish stores.

The pizza delivery chain said that its UK sales rose by 11.7% to £147.6m.

''These results are particularly pleasing as they come on top of very strong comparatives from last year, highlighting the underlying strength of the core UK business,'' the company said.

However, the company warned that annual losses at its fledgling German business would be higher than anticipated due to increased training costs and a poor performance at some of its stores, sending its shares lower in London trading.

The company said it expected losses for the year at its two-year-old German arm to be between £2-3m more than first thought, taking the total anticipated loss to as much as £6m, according to analysts.

Domino's said like-for-like sales at its six German stores open for more than a year rose 11% in the period, representing a big slowdown from growth of 40% in its first quarter. Of the 25 stores now in Germany, the stores it manages directly were significantly underperforming those run by franchisees and would be switched to a franchised model "as soon as practicable", it said.

Domino's has previously said the German business could eventually outgrow its core British arm, which owns the master franchise to own and operate the Domino's brand in the UK, Ireland and other European countries. It has said it expects its German business to be profitable by the end of 2015 and will open another 12 stores in Germany in the second half of this year.

"I am very pleased with the overall results for the first half - particularly with regards to the UK and Ireland'', commented Lance Batchelor, the company's chief executive.

''Our system leads the leisure sector and, with the majority of our business coming via web and mobile platforms, we are now truly an online retailer,'' he added.