A Z Oamaru service station staff member told Star.kiwi they later learned they had served the accused, but they were not allowed to give any information.
Z head office would also not comment.
Star.kiwi asked police if there was a risk to the public in regards to the explosives when the accused stopped for fuel in Oamaru.
"While the investigation is ongoing we are not in a position to go into specifics around those inquiries.
"The matter is now before the courts and we will not be jeopardising any future prosecution," a police spokeswoman said.
Police have used CCTV footage from many locations between Dunedin and Christchurch to follow the accused's journey, which is part of the evidence for the prosecution's case.
The accused has pleaded not guilty to 51 murder charges, 40 attempted murder charges and one terrorism charge.
A High Court trial is scheduled for May next year.
- Star.kiwi