Chief Executive Uwe Krueger said on Thursday that he would consider bolt-on deals to grow those two key business units, adding to the acquisition of two specialist energy firms in North America in the first half -- Nuclear Safety Associates and Houston Offshore Engineering.

"Asia Pacific and energy will remain the focus areas of our growth and also for our investments," he told Reuters.

Energy and Asia currently account for 15 percent of revenue.

The 76 year-old firm, which maintains some of Britain's railways and roads but also builds water parks and supports air traffic controllers, reported an underlying pretax profit of 46.9 million pounds ($74 million) in the first half, helped by strong performances in its Middle East region and energy.

It also raised its interim dividend by 4.8 percent to 11 pence but added that the impact of a strong pound hit earnings by 2.7 million in the first half of the year.

Shares in the company were broadly flat at 13.64 pence by 0847 GMT.

"This is a good first half for Atkins despite the currency impact and in the second half it will get stronger support from recent acquisitions, especially Nuclear Safety Associates," said analyst Stephen Rawlinson at brokerage Whitman Howard.

(1 US dollar = 0.6340 British pound)

(Editing by David Clarke and Clara Ferreira Marques)

By Li-mei Hoang