FRANKFURT (Reuters) - Lufthansa's (>> Deutsche Lufthansa AG) budget unit Eurowings has pushed back the start of some long-haul routes as it grapples with costly delays that have grabbed headlines in Germany.

Eurowings will commence routes to Boston and Miami from Cologne in June, a month later than originally planned, a spokesman said on Wednesday. A planned route to Tehran in Iran has also been put on hold.

While Eurowings is mainly aimed at the short-haul market, the carrier is also offering cut-price flights from Germany to further-flung tourist destinations such as Cuba, Thailand and Mexico.

But with a fleet of only two long-haul jets, delays have been stacking up when technical problems occur, including one incident that resulted in a delay of over 60 hours on a flight from Cuba.

Parent group Lufthansa has temporarily taken control of a route to Dubai while Eurowings works on stabilising the operation.

The unit is due to receive two more A330 long-haul jets over the next two months and aims to have a fleet of seven wide-body planes by 2017.

Lufthansa wants to make Eurowings the third-largest low-cost carrier in Europe, behind Ryanair (>> Ryanair Holdings plc) and easyJet (>> easyJet plc), as it seeks to tap into growing demand for leisure travel and fend off its rivals at home in Germany.

(Reporting by Peter Maushagen; Writing by Victoria Bryan; Editing by Elaine Hardcastle)

Stocks treated in this article : Deutsche Lufthansa AG, Ryanair Holdings plc, easyJet plc