Shares in engineering and contracting firm Transfield Services are almost 10 per cent weaker despite an 80 per cent rise in half year profit.

The operator of detention centres at Nauru and on Manus Island, as well as maintenance and construction services in the resources, defence and infrastructure sectors, said its diversity helped to overcome a sharp drop in earnings from its mining sector operations.

Transfield made a net profit of $8.4 million in the half year to December 31, up from $4.8 million in the same period a year earlier.

But its earnings growth of 14 per cent to $98.3 million missed market expectations, Quay Equities head of trading Tristan K’Nell said.  Its defence, social and property operations were the company’s biggest earner in the half year after a substantial rise from 12 months earlier, but earnings from infrastructure and resources fell.

Transfield also confirmed there had been no further developments in its recent takeover talks with Spanish infrastructure group Ferrovial, after Transfield rejected a $1 billion offer in December.

The company is also set to change its name in 2015, as the owner of the Transfield trademark, Transfield Holdings, has requested a termination of the trademark agreement after selling out of the company in 2014.

Transfield confirmed its full year guidance of underlying earnings between $260 million and $280 million, up from $217 million in the previous financial year.