There are fears that a coal ship which has run aground near the Great Barrier Reef could break up, spilling more oil into the pristine waters of the marine park.

The Chinese vessel Shen Neng 1 ran aground on Douglas Shoal, east of Rockhampton near Great Keppel Island, on Saturday.

Authorities say the vessel is balanced precariously on the shoal and could break up. The crew is still on board.

It is estimated that damage to the ship's hull and fuel tanks has caused a narrow spill of three to four tonnes of oil about three kilometres in length and 100 metres wide.

Maritime Safety Queensland spokesman Patrick Quirk says authorities are focusing on stabilising the ship to minimise the exposure and further risk to the reef.

"We have helicopters in the air assessing the damage around the ship. Indications are that any oil spill would have been on a very small amount," he said.

It is unclear why the ship was travelling in a restricted part of the Great Barrier Reef Marine Park. Several state and federal agencies are investigating the incident.

Like many ships, it did not have a marine pilot with specialist local knowledge on board.

The Federal Opposition says Australian Defence Force assets should be made available to help salvage the ship.

Opposition environment spokesman Greg Hunt says the situation has to be dealt with quickly.

"What we need to make sure is that the Prime Minister is personally in charge, that he assumes responsibility, and therefore appropriate

Defence assets should be made available," he said.

"The ship could easily break up, and to be wise after the fact will be an environmental disaster for the Barrier Reef."

Salvage workers will deliver an initial report today about the condition and future of the ship.

Maritime Safety Queensland spokesman Mark Strong says they have sprayed the spill with chemical dispersants and may do so again today.

"The first run seemed to lead to an improvement in the oil clean-up. It certainly dispersed some of the oil that was there," he said.

"It is a heavy fuel oil and as such is more resistant than normal to chemical dispersants, but the best time to attempt to disperse oil with chemical dispersant is in the first 24 hours."

He says the ship must have been travelling well off course when it became stuck in a protected reef.

Mr Strong says a local navigator had been on the ship to guide it into open water but left before the accident occurred.

"The area is an environmentally sensitive area and... all shipping is banned from using that environmentally sensitive area," he said.

"As a result, the vessel was significantly off the course that it should have been on."

Queensland Premier Anna Bligh says a second salvage tug should be on site by about midday, but it is a very complex operation.

Yesterday Ms Bligh said it was not known why the ship was in a restricted part of the Great Barrier Reef Marine Park.

But Mr Strong says it could have been much worse.

"This spill certainly is not as bad as it could initially have been," he said.

"We still have only a small amount of fuel in the water.

"It is fuel from the vessel itself and that's why we're taking every precaution before a decision is made on how the vessel may be salvaged."

'Big concern'

Island resident Carl Svendsen makes his living from the reef and is familiar with the area 70 kilometres east of the island where the ship ran aground.

"[I'm] quite shocked to hear in this day and age that a ship had run up on the reef out here in reasonable weather conditions," he said.

"In that particular area the reef is very pristine. So you've got all your coral reef and there's all the sea birds around.

"For example, very large seabird populations nest and breed there so this is just about in visible distance, just over the horizon from there. So [it is] a very big concern for us."

Marine geologist Dr Greg Webb from Queensland University of Technology is also familiar with the incident site.

He says the good news is that the reefs are well spaced out, however the spill will add extra strain where it is not needed.

"The reefs are terribly resilient. If you apply enough different stresses to them all at once, we really don't know what the effects could be," he said.

"In the past we always just thought a reef could put up with anything, and I guess over the last decade or so, we're beginning to understand that maybe they can't."

Just last year the container carrier Pacific Adventurer spilled a large amount of oil after striking trouble off Moreton Island and Queensland's Sunshine Coast.

Federal Environment Protection Minister Peter Garrett says he will await the results of an investigation before passing judgment on what happened in the latest incident.

Mr Garrett points out that the Queensland Government is leading the operation with assistance from the Commonwealth. It will be up to the Commonwealth, however, to determine whether charges should be laid.