Petrofac reported a net loss for the first half, hurt by a steep increase in costs at its Shetland Islands project, and said it still expected net profit for the year to be weighted towards the second half.

Shares in the oilfield services company rose 2.4 percent to 748.5 pence on Tuesday on the London Stock Exchange.

Oil and gas companies are scrambling to rein in costs and preserve margins as crude oil prices continue to hover at 6-year lows, suffering under a supply glut and weakening demand.

Adding to the oversupply concerns is the imminent lifting of the sanctions on Iran, which British foreign minister Philip Hammond said could be as early as next spring.

Iran, which holds about a tenth of the world's proven oil reserves and 18.2 percent of natural gas reserves, however, represents tens of billions in contracts for oil services companies.

Petrofac would seek to enter the Iranian market once major oil and gas companies start entering into contracts with local operators, Chief Financial Officer Tim Weller said.

"Given our strength in the middle eastern region, it will be a natural extension of our core onshore EPC (engineering, procurement and commissioning) business to start work in that particular country," he said on a call with journalists.

Representatives of Petrofac's rivals, Amec Foster Wheeler and Scottish industrial engineering firm Weir Group , visited Tehran last weekend as part of a delegation led by Hammond who reopened the UK embassy.

Petrofac posted a net loss of $133 million for the six months ended June 30, after recognising $236 million in losses from its Laggan-Tormore project in the Shetland Islands, compared with a net profit of $136 million a year earlier.