'I was taken into an interrogation room after customs officials read my diary.'

A Melbourne woman says her “Hawaii dream turned into a nightmare” when she was detained by immigration authorities while trying to visit her boyfriend in the US.

Molly Hill, 26, had been planning a three month trip to the US with an 88-day tourist visa but says she never made it because of several, apparently suspicious, notes in her diary.

“I was taken into an interview room and had every inch of my luggage searched,” the communications student wrote in a furious Facebook post.

"[They] understood that I have an American boyfriend and I spent about six hours in and out of the interrogation rooms.

"In the end, they were convinced I wanted to immigrate illegally because my diary had notes like 'going away drinks' and 'last day at work', things I got in order before expecting to be away for three months."

Hill claims she was then forced to spend the night in a Federal Detention Centre in Honolulu before having to fork out $620 for a flight home.

"I was told there were no more flights to Australia that day and I would have to spend the night at the detention centre, which the officer described as 'like jail but you can't make any phone calls'," she wrote.

After allegedly being subjected to a strip search involving a "squat and cough", the young woman was handed an apple and a sandwich and spend the night sharing a cell and a single bunk with another woman.

The next day, which happened to be her birthday, Hill says she was woken up by a flashlight and an officer yelling in her face that she was being released.

She declined her "oatmeal slops", changed and was searched a second time, and then escorted to the airport in handcuffs.

"It's been a surreal few days that's taken a big chunk of money, heartache and tears," she wrote.

Speaking with Nine News on Thursday afternoon, the young woman said she was shaken by the incident and couldn't fathom how is was "normal process", but a spokesperson from the US Customs and Border Protection had told the news organisation there had been "[no] wrongdoing of any kind".