Australians and New Zealanders turned out in record numbers Monday morning to mark the 90th anniversary of the battle of Gallipoli, a disastrous First World War campaign that left 100,000 soldiers dead.

In the focal point of the memorials, thousands of people gathered in what was thought to be the largest crowd ever to attend the annual dawn service at Anzac Cove on Turkey's Gallipoli peninsula.

The cove takes its name from the Australian and New Zealand Army Corps (ANZAC), whose troops waded ashore on April 25, 1915.

Thousands gather to commemorate the 90th anniversary of the battle of Gallipoli. (AP Photo)

They fought under British command in a bloody nine-month campaign to capture Istanbul and open a Black Sea route to Russia.

The battle is seen as a defining moment in the history of the young nations of Australia and New Zealand, where Anzac Day has become a memorial day for all fallen troops and both countries' biggest national holiday.

Members of the crowd at Gallipoli's North Beach – many draped in Australian flags – watched as a light display lit the cliffs where the Anzacs were forced to dig in.

Then they listened to a service that included words from Australian Prime Minister John Howard, his New Zealand counterpart Helen Clark and Britain's Prince Charles.

25,000 gather in Sydney

In Australia's largest ceremony, about 25,000 people attended a dawn service in central Sydney.

Dozens of other marches and memorials were held throughout the country and New Zealand, and Australian forces held ceremonies and commemorative barbecues at overseas postings.

Some 8,709 Australians and 2,701 New Zealanders were killed in the fighting at Gallipoli, along with more than 21,000 British troops, 9,800 French soldiers and more than 1,300 Indian troops. Thousands more were wounded.

On the other side, Turkey lost some 86,000 men in the campaign, but forced the Allies to withdraw from the peninsula.

Gallipoli took place only 14 years after a number of former British colonies came together to form Australia and was the first battle where Australians fought under their own flag.

With reports from the Australian Broadcasting Corp. and Agence France-Presse