Marine scientists from different parts of the world meeting in Cairns this week are urging the Gillard government to step up protection of the Great Barrier Reef.

The experts are in Queensland for the 12th International Coral Reef Symposium to tackle the latest research and management practices in their field.

In making the push, Terry Hughes, director of coral reef studies of the Australian Research Centre, cited a UNESCO report that the Great Barrier Reef, a World Heritage site, is endangered due to threats from coastal developments which needs to be dealt with better.

Laurence McCook, science co-ordinator of the Great Barrier Reef Marine Park Authority, estimates the contribution of the reef to the Australian economy at $5.5 billion a year, and the cost of managing it at 0.7 per cent or $385 million.

Over 2,600 marine scientists from 80 countries are expected to sign a consensus statement to urge governments to accord more protection to the world's reefs.

The UNESCO report asked the Queensland government to reject approval of any new port development or related infrastructure outside of existing ports.

The Australian Reef Pilots (ARP) also sought mandatory pilotage of ships throughout the entire marine park because of frequent violation of laws. Simon Meyjes, chief executive of the ARP, disclosed that every two days. one ship that passes the area fails to report its position before entering the Reef.

Australia mandated vessels that are 50 metres or longer and all oil tankers to report their position before they enter the marine park area to allow automatic tracking and for them to be warned if they stray off course. The new rules were put in place as a result of the 2010 grounding of a Chinese bulk carrier, the Shen Neng 1, which had 65,000 tonnes of coal and ran aground on Douglas Shoal. The accident, which took place 80 kilometres north of Rockhampton, caused a 3-kilometre long scar in the reef and spilled tonnes of oil.

The accident led to the mandatory reporting and vessel tracking requirement which was extended to the southern border of the reef. However, most of the 250 cases of ships that passed the marine park in the past 18 months breached the regulation, Mr Mayjes said.

He explained the frequency of the violations to foreign crews aboard the ships lacking knowledge of Australian maritime laws designed to prevent an oil spill.

Despite the failure of some foreign vessels to report their entry, the Great Barrier Reef and Torres Strait Vessel Traffic Service uses satellite-tracking to monitor the ships that enter the marine park, said Mick Bishop, the director of the service.