* 6 mln Galaxy S6, S6 edge sales in April - Counterpoint
* Researcher says sales of new models outpacing Galaxy S5
* Samsung stock pressured in recent weeks on sales worries (Updates with comments from Counterpoint, background)
SEOUL, June 2 (Reuters) - Sales of Samsung Electronics Co Ltd's flagship Galaxy S6 smartphones reached 6 million units at the end of April, less than a month after their launch, researcher Counterpoint said on Tuesday, suggesting a positive start.
Counterpoint said in a statement that combined sales of S6 and S6 edge from the April 10 launch to April 30 were better than Galaxy S5's sales in the same period of 2014.
They were also the most popular smartphone models globally after arch-rival Apple Inc's iPhone 6 and iPhone 6 Plus, the researcher said.
The data, which counts sales to customers as opposed to shipments, suggests the new flagship devices will help the world's top smartphone maker regain momentum following a disappointing 2014. The new phones were well-received by critics, buoying hopes for an earnings turnaround.
Though Samsung executives have maintained the S6 models would set a new company shipments record, the firm has not disclosed sales numbers so far. Investors have grown worried that sales may not meet expectations, which contributed to the stock's 7.3 percent decline in May.
While the flat-screen S6 sold more in April, the researcher said sales of the curved-screen S6 edge would have been higher had it not been for supply constraints. Samsung has said supply problems for the edge model will be resolved within the current quarter.
"The Samsung Galaxy S6 series has a chance to become the top selling smartphone overtaking Apple's iPhone 6 series, if production issues are solved," Counterpoint Research Director Peter Richardson said in a statement, adding the window of opportunity for the Samsung devices to achieve that goal would be small given the intense competition.
Counterpoint said it expected sales for the new Samsung flagship phones to reach 50 million by the end of the year, better than what the firm estimates to be its current first-year sales record of 45 million units for the Galaxy S4. (Reporting by Se Young Lee; Editing by Miral Fahmy and Mark Potter)