MBIE was also investigating, but the ministry itself had not confirmed the fuel was contaminated, its trading standards national manager Stephen O’Brien said.
“This matter is currently still under investigation and the existence or source of any potential contamination has not been confirmed at this stage,” he said.
“This investigation will also include determining whether any potential contamination occurred on the vessel or in the supply chain.”
It had tested samples of fuel supplied to the vessel and had not identified any problems with the fuel as it was supplied, O’Brien said.
“We have expanded our testing scope to include a number of historical fuel deliveries, and we expect these test results next week.”
StraitNZ told the ministry on Monday that fuel may have been a factor in the Connemara’s power loss, he said.
Resources Minister Shane Jones said he was not concerned about any widespread problems with fuel in New Zealand.
His office told RNZ he would await the outcome of MBIE’s investigation.
Meanwhile, the union representing ship masters and officers said StraitNZ and Maritime NZ should have fronted up on the Connemara’s problem immediately, in case it happened to any other vessel.
Maritime operators needed to know how to prevent further issues, Merchant Service Guild’s vice-president Iain MacLeod said.
But Maritime NZ said testing showed there were no problems with fuel supplied out of Wellington, and if there were, it would have notified the appropriate people.
Transport Minister Simeon Brown said he was satisfied with Maritime NZ’s communication with him and the public.