The Federal Government will leave “no stone unturned” to assist the investigation into the disappearance of backpacker Britt Lapthorne in Croatia, Prime Minister Kevin Rudd says.

The 21-year-old Australian disappeared in the early hours of September 18 in Dubrovnik.

Mr Rudd said several Australian Federal Police (AFP) officers had been sent to Croatia and the Federal Government had been working with authorities on the ground since they were notified.

Mr Rudd said he understood how hard the situation was for any family who had a loved one go missing.

“We take every case seriously because it could be our kids any day,” he told reporters in Sydney.

“At any one time there are a million Australians offshore.

“Our job is to do whatever we can to help families who find themselves in these horrible circumstances.

“We will leave no stone unturned through the federal police, through our diplomats, through consular officials, through our political contact with the government to do whatever we can do to assist in this rally hard and difficult matter.”