Australia is not on the itinerary for the royal couple’s tour of the region but it was foremost in their minds on Thursday.

As the sun cut through Singapore’s sticky morning mist, William and Kate arrived at the Kranji war memorial in Singapore, where nearly 4500 World War II casualties are buried or commemorated.

The site also bears the names of over 24,000 Commonwealth servicemen with the land air forces who have no known grave.

But it was the bone-coloured headstones of a small group of nine Australian soldiers and one British marine, known as “Z special unit”, which the future king most wanted to see.

“The Prince was aware of Z Force and was keen to visit Z Force,” said group captain Clive Coombes, who showed the couple around the manicured lawns to the row of graves.

“(He) recognised that this was a huge amount of resistance towards the end of the war.”

The special unit was tasked with destroying Japanese ships in Singapore Harbour and attached bombs to the vessels by sneaking up on them in canoes.

Their first operation was successful, striking a major blow against the Japanese war effort, but all of them were either captured or killed during a second mission.

Ten men survived – nine Australians and one British Royal Marine – but they were executed just weeks before the end of the war, when the Japanese knew they were losing.

“These 10 guys became known as heroes, particularly in Australia,” said Mr Coombes.

It was a sombre moment for William, who has worked as a fulltime pilot with RAF’s Search and Rescue Force since 2009.

Kate wore a floating bespoke duck egg blue dress by Jenny Packham, giving the British designer an outing for the second time this tour.

The buttoned V neck top tapered in at the waist to fall in soft pleats to her knees, teamed with tan shoes.

After a minute’s silence and the laying of a wreath, Kate was handed a white parasol to shade her from the scorching sun before touring the graves at the picturesque cemetery.

The royal visit coincides with the 70th anniversary of the Battle for Singapore, in which more than 1000 Australians were killed or went missing in action and more than 15,000 Australians became prisoners of war.

Over a third of them died of starvation, illness and brutality in captivity.

William and Kate are jetting out of Singapore about midday for Malaysia, where the Duchess will give her first overseas speech at a hospice.

It’s then off to a Diamond Jubilee tea party thrown by the British High Commissioner and a glamorous dinner hosted by the country’s king – His Majesty The Agong – in his magnificent Istana Negara palace.