Mr Shearer said a Labour Government would make improvements to safety measures and increase local involvement.
"[Currently] we do not have New Zealanders overseeing the exploratory rigs doing the drilling. We should have our own people on the ground."
Equipment to respond to an oil spill had to be on site and ready to go in case of an accident, he said.
However, Anadarko's current oil clean-up plan would take at least a month to plug a leak, and 115 days for a rig to arrive.
Asked whether drilling was acceptable under those circumstances, Mr Shearer dodged the question, instead drawing parallels with the airline industry.
"It's very very safe, but when it goes wrong, it goes very very wrong. And what we want to have is an Air New Zealand rather than an Air Togo."
Following a fruitless summer of oil exploration, Mr Shearer was asked whether the $12 billion oil drilling industry touted by National was "a mirage".
"It's anybody's guess," he said.
"Putting all our cards on the table and say 'our economic development is going to depend on the discovery of oil' is nonsense. It's like walking into a casino and hoping the ball lands on number 36."
Royalties could be raised when more oil was discovered, but hiking them now would "kill the industry", he said.
Mr Shearer said the policy wouldn't affect a potential coalition with the Green Party.
His comments come amid National Party plans to allow oil and gas drilling in a marine sanctuary, home to the critically endangered Maui 's dolphin.