Qatar hopes a merger between German builder Hochtief and Spanish construction and services group ACS will be 'friendly,' Qatar's Prime Minister Sheikh Hamad bin Jassim bin Jabr al-Thani said on Monday.

'We are hoping for goodwill that the merger will be friendly. We don't believe in a hostile takeover,' Sheikh Hamad told reporters on Monday.

Qatar agreed to buy a 9.1 per cent stake in Hochtief for 400 million euros, adding muscle to the No.1 German builder's fight against a hostile takeover approach from rival ACS in December.

ACS earlier this month passed the 30 per cent threshold with its stake in Hochtief, allowing it to raise its holding further without another full bid.

Hochtief's chief executive, who has fiercely fought ACS's attempt to take control, has said he is proceeding with the sale of the group's concessions business, a move that could make it more expensive for ACS to get a controlling stake.

Sheikh Hamad is also head of Qatar Investment Authority, the state's sovereign wealth fund. He was speaking at a joint conference with Spanish Prime Minister Jose Luis Rodriguez Zapatero.

Last week, Qatar said it was open to buying stakes in part state-owned British lenders RBS and Lloyds Banking Group.-Reuters