Police have arrested the son of a hostel owner in Croatia over the disappearance of Australian backpacker Britt Lapthorne, the Nine network reported.

Ivica Perkovic, whose father owns the backpackers’ hostel where Lapthorne, 21, was staying, has denied any involvement but was being held in cells at police headquarters in Dubrovnik.

Investigators aren't yet naming him as a suspect, Nine reported.

A spokesman for the Department of Foreign Affairs and Trade (DFAT) said he could not confirm whether an arrest had been made.

"I can't confirm that as it is a matter for Croatian authorities," the spokesman said.

An earlier statement from DFAT said consular staff were in close contact with the Australian Federal Police, with whom Lapthorne had been registered by her family as a missing person.

Perkovic said he saw Lapthorne on the night she was last seen.

"I was not the last person she saw. The only time I saw her was just for a few minutes. This was around the table at around 10 p.m. that night," he said.

Police asked him about a phone call Lapthorne made to his mobile phone, he said.

"There was one call and police interviewed me. There was one call found on her mobile phone, which is the official phone of the backpackers' hostel, so everyone ... has that phone."

Lapthorne’s father, Dale, began the journey to Croatia from Melbourne today to join the search.

Click here to read more on this story at News.com.au.