Strong performances from its wind and road businesses were the main factors behind a 40 per cent rise in first-half operating profit at infrastructure group, NTR.

But the company's waste management division had a slower start to the year while its broadband business ran up a loss of €4 million.

Overall, revenues at NTR grew by 34 per cent to €169 million while operating profits rose by 40 per cent to €12.4 million. But a 79 per cent rise in the company's interest bill to €8.2 million, reflecting the cost of a significant capital programme undertaken in the second half of 2004 and the first half of 2005, hit pre-tax profits, which fell by 19 per cent to €10 million.

The company announced an interim dividend of 1.5 cent per share, a 10 per cent increase.

NTR's toll business, which includes the controversial West Link toll bridge, saw pre-tax profits increase to €13.3 million from €7.5 million, including a €4.3 million gain from a land sale.

The company paid €21.7 million to the State from its tolling income, including €1.86 million in relation to an underpayment of the licence fee in 2002 and 2003.

NTR's finance director Michael Walsh said the company was engaged with the National Roads Authority (NRA) in a bid to relieve congestion on the M50. He sees one of the solutions to the problem as the introduction of barrier-free tolling.

Meanwhile, Airtricity, NTR's alternative energy business, delivered a 43 per cent increase in first-half sales to €86.4 million as it commissioned a further 113 megawatts of wind electricity generating capacity in Ireland and Scotland.

Greenstar, the company's waste management business, had a slow start to the year due to increased competition and lower pricing, which NTR believes was caused by a drop in waste volumes following the introduction of the new pay-by-weight system.

However, the company said the division, which posted an 18 per cent rise in first-half sales to €47.5 million, was now back on track, helped by a very active sales effort.

Irish Broadband racked up losses of €4 million as the company continued to invest heavily in the fledgling business. Mr Walsh said it was on target to have 20,000 customers by year- end. But the company, which raised €13 million in debt funding through NCB Stockbrokers earlier this year, will probably need to fund raise again later this year or early next year, he said.

Shares in NTR, which trades on a "grey market" operated by a number of stockbroking firms, were unchanged yesterday at €3.35 as they remained untraded.