Oil extended gains in Asian trading on Monday as a weaker dollar and easing worries over Britain's possible exit from the European Union helped support crude.
London Brent crude for August delivery was up 34 cents at $49.51 a barrel by 0235 GMT, after settling up $1.98, or 4.2 percent, at $49.17 on Friday.
NYMEX crude for July delivery, which expires on Tuesday, was up 44 cents at $48.42 a barrel, after closing up $1.77, or 3.8 percent, on Friday.
Campaigning for Britain's vote on EU membership resumed on Sunday after a three-day hiatus prompted by the killing of a pro-EU lawmaker.
Three opinion polls ahead of Thursday's vote showed the 'Remain' camp recovering some momentum, although the overall picture remained one of an evenly split electorate.
"It is hard to think the market's calmer tone... is going to be an ongoing theme this week, particularly as Brexit campaigning and the release of opinion polls has resumed again," ANZ said in a morning note.
The pound was up against the dollar at $1.4450 from $1.4350 on Friday. The Japanese yen held not far from its highest level against the dollar in almost two years.
Oil prices continued to recover despite data showing U.S. energy firms adding oil rigs for a third week in a row, suggesting higher production to come.
Oil services firm Baker Hughes reported nine rig additions in the week to June 17.
France's CGT union ended a strike on Friday that had paralysed traffic for 26 days at the Fos Lavera oil terminals on the Mediterranean, the country's biggest oil hub, a management official at port operator Fluxel said.
