Spanish oil and gas group Repsol reported Thursday a boost in net profits in the first quarter of 2013, saying the gain would have been much greater but for last year's expropriation of its Argentine offshoot YPF. Repsol said net profit edged up 1.6 percent from a year earlier to 631 million euros in the quarter, assuming a constant cost of supplies (CCS) as is widely accepted for the reporting of financial results in the oil industry. The Argentine government in May last year nationalised oil and gas firm YPF, reducing Repsol's 51-percent stake to just 6.4 percent and whipping up a diplomatic row between Madrid and Buenos Aires. Repsol is fighting for financial compensation over the expropriation. When the impact of the YPF seizure was stripped out of its results, the oil giant said net profit gushed 38.4 percent higher to 634 million euros ($830 million). And excluding other one-off gains and losses, the adjusted net profit soared by 47.0 percent to 676 million euros. Repsol said the key drivers behind profits were bigger margins and volumes in its sales of liquefied natural gas in North America where the business scenario was improving. Excluding the impact of the YPF expropriation and other changes in Repsol operations, the group's total production climbed 11.4 percent to the equivalent of 360,300 barrels of oil a day, largely because of its activities in Trinidad and Tobago. Repsol unveiled a new strategic plan in May last year after losing control of YPF, focused on boosting oil exploration and reducing its net debt to avoid a possible downgrade by credit rating agencies. As part of the strategy the company said it would invest 19.1 billion euros between 2012 and 2016 to develop new exploration projects, mostly in Algeria, Brazil, Bolivia, Russia, the United States, Spain, Peru and Venezuela. The group also provided results for the latest quarter that incorporated variations in the value of its inventories. These figures showed that net profit excluding operational changes such as the expropriation of YPF rose 1.3 percent to 637 million euros and net profit including such operational changes slumped 19.9 percent to 634 million euros.