ABUJA - Nigeria is planning to auction seven deep offshore oil blocks, 15 years since the last ones were auctioned, the upstream regulator said on Saturday.

Apart from marginal fields, Nigeria last conducted bidding for 45 oil blocks in 2007 even when the court had stopped the sale of two that were under litigation between Shell and the Nigerian government.

"We will announce by next month the intention to conduct a transparent bidding rounds for seven oil blocks", Gbenga Komolafe, chief executive officer of the Nigerian Upstream Petroleum Regulatory Authority, told Reuters.

"All the blocks are in the Lagos waters, not in the Niger Delta with the added advantage of its proximity to the export free zone in Lagos," he said.

In 2005, then President Olusegun Obasanjo launched an open auction process and said Nigeria would no longer award lucrative drilling licences on a discretionary basis.

However, the auctions drew criticism that they were neither as transparent as they should be nor as successful in terms of securing investment Nigeria.

(Reporting by Camillus Eboh, Editing by Angus MacSwan)