* Output rises 70,000 bpd from May

* Group exceeds target by about 280,000 bpd

* Details by country

LONDON, July 2 (Reuters) - OPEC oil output rose in June for a second consecutive month, a Reuters survey found on Tuesday, as higher supply from Nigeria and Iran offset the impact of voluntary supply cuts by other members and the wider OPEC+ alliance.

The Organization of the Petroleum Exporting Countries pumped 26.70 million barrels per day (bpd) last month, up 70,000 bpd from May, according to the survey based on shipping data and information from industry sources.

The increase comes despite OPEC+, which comprises OPEC and allies such Russia, deciding last month to extend most of its output cuts until the end of 2025 to bolster the market in the face of tepid demand growth, high interest rates and rising U.S. production.

Nigeria raised output by 50,000 bpd and there were smaller increases from Iran and Algeria as oilfield maintenance was completed. The largest drop, of 50,000 bpd, was in Iraq, though the country is still exceeding its OPEC+ target.

OPEC pumped about 280,000 bpd more than the implied target for the nine members covered by supply cut agreements, with Iraq still accounting for the bulk of the excess, the survey found.

Among those not required to cut output, Iranian output reached 3.2 million bpd. That matched a rate posted in November 2023, which was the highest since 2018, according to Reuters surveys.

Iran is selling crude oil to 17 countries, Oil Minister Javad Owji was quoted as saying by the semi-official Mehr News Agency on Tuesday, indicating that some states may not be honouring U.S. sanctions that remain in place.

The Reuters survey aims to track supply to the market and is based on shipping data provided by external sources, LSEG flows data, information from companies that track flows - such as Petro-Logistics and Kpler - and information provided by sources at oil companies, OPEC and consultants. (Additional reporting by Ahmad Ghaddar Editing by Jason Neely and David Goodman )