Abu Dhabi investment firm Waha Capital said on Sunday it had bought a 20.56 percent stake in Dubai-based oilfield services firm National Petroleum Services for $76 million, as part of an increased emphasis on the region's energy sector.

In April, a consortium of Gulf-based investors including Fajr Capital and Arab Petroleum Investment Corp (APICORP) agreed on a deal to acquire NPS; Fajr said at the time that the deal was worth more than $500 million.

Waha said in its bourse statement on Sunday that it was part of the consortium and that the deal, with a total equity value of $370 million, had now closed. It did not explain the difference between its valuation of the acquisition and the figure given earlier by Fajr.

NPS, with about 1,300 employees and 20 subsidiaries, operates in the Middle East, Malaysia, North Africa and Brunei, offering services including oil well servicing and testing.

Waha said it had established a new unit to drive its future investments in the energy sector across the Middle East and North Africa.