New Zealand authorities said Thursday that oil washing up on its beaches was likely stirred up by stormy weather conditions and not from a new spill. Maritime New Zealand, the agency responding to grounded cargo vessel Rena, has battled high seas and stormy weather in its effort to get oil out of the ship. Andrew Berry, an on-scene commander for the Rena response, called for patience as oil continued to show up on New Zealand beaches. \"While we are making every effort to clean the beaches, this residual oil will continue to surface -- this is just part of the process and people will need to be patient,\" he said in a statement. \"We will continue to direct our cleanup crews to areas where there are high concentrations of this oil coming ashore.\" Rough weather forced salvage teams to abandon Rena early this week, though authorities said 22 workers were back on the ship. Divers were working to get the remaining 358 tons -- around 2,600 barrels -- of oil from a submerged fuel tank on the starboard side of the ship, which suffered major structural damage when the ship ran aground in early October.