Tauranga man Allan McKee said ship staff dropped the anchor to stop it hitting the rocks, and he had seen large plumes of black smoke billow from the funnel of the ship as it tried to reverse off the rocks.
The ship was towed further out to sea while experts assessed it for damage, and was expected to be brought back into port later today.
The Rena remains stranded on Astrolabe Reef off Mount Maunganui nearly a month after it ran aground.
About 350 tonnes of oil has spilled from the container vessel, killing more than 1000 seabirds and forcing massive coastline clean-ups.
Since the Rena crash, the Greens have made repeated calls for a Royal Inquiry, and Mr Hughes said today's crash underlined the need for a wider investigation into the shipping sector.
"It's fantastic to hear there's been no oil spilt, there're no injuries and that it was a comparatively minor incident, but it does raise some serious concerns with two accidents in around a month's time at New Zealand's busiest port.''
Among his biggest concerns was the deregulation of the industry, the training of Filipino crews, and Maritime New Zealand's preparations and funding.
"There are a whole number of questions and we are not necessarily going to get a critical response from either the salvor, Svitzer, or Maritime New Zealand, that's why it has to be independent.''
The Maori Party has joined the calls for an inquiry, saying there should be a focus on strengthening regulations on coastal shipping and placing levies on vessels carrying oil.
It also called for foreign vessels to be required to have a New Zealand pilot on board at their cost.
