The Topaz consortium will lease out its interest in a Galway oil terminal as a gesture of goodwill to the Competition Authority after the inadvertent clearance of its multimillion-euro deal to buy Statoil's Irish unit.

The agreement goes some way to save face for the authority, which was severely criticised after an internal error led it to miscalculate the statutory deadline for its official scrutiny of the transaction by one day. The deal received automatic clearance last Monday after the authority missed the legal deadline to impose restrictions on Topaz.

Already the owner of the former Shell business in Ireland, Topaz has also agreed to sell a filling station at an undisclosed location in Dublin where a Statoil outlet was in close proximity to a Shell station.

The agreement between Topaz and the authority included a third undisclosed issue, which was "resolved" by both sides. Topaz and the authority said the issue in question did not have any material impact on the scope of the transaction.

The authority's spokesman said the agreement addressed all of the competition concerns it had about the Topaz-Statoil deal, which creates the biggest oil distribution operator in the State.

While Topaz made proposals last month to meet the authority's concerns, the consortium had been free to withdraw them after the deal received unwitting clearance. In the event, Topaz chose to leave the proposals on the table.

If it had not done so, the authority would have been open to the accusation that its error had resulted in the legal approval of a transaction which might otherwise have been restricted.

"The implications of the transaction had been the subject of extensive discussion between Topaz, our legal advisers McCann FitzGerald and the authority over the weeks since its first announcement in June last," said Topaz chief executive Danny Murray. "That process had, to our mind, clarified the issues of potential concern to the authority. We made proposals to the authority which we believed answered fully those concerns.

"We were confident that those proposals would have formed the basis for an early approval of the transaction by the authority. We have now discussed these matters with the authority and confirmed to them that we are willing to stand by these proposals in full."

The authority had cited concerns about the terminalling and wholesale supply of refined petroleum products in Connacht, particularly in Galway, where the acquisition would reduce the number of independent terminal operators from three to two.

It also had concerns about the operation of motor fuel retail stations. "Based on a thorough analysis of the individual local markets affected, the acquisition would have reduced competition in retail stations in only one Dublin area," it said.

"The Competition Authority undertook a comprehensive analysis of the respective retail networks of Topaz and Statoil which comprise 347 outlets nationwide... The acquisition would have led to competition concerns in only one local market, located in Dublin. Topaz has agreed to a solution in this area that resolves the Competition Authority's competition concerns."