Routine checks are made on visitors to the UK
A Brazilian woman was refused entry to the UK when she arrived at Newcastle Airport with luggage containing only T-shirts, a dressing gown and lingerie.
UK Border Agency officials said they suspected the 32-year-old of being involved in the sex industry.
She had arrived on a flight from Geneva on 4 April, the agency said.
Airport staff became suspicious when she could not say what she would be doing in the UK, other than "seeing Newcastle city centre".
Checks revealed the woman had been refused entry to the UK at Belfast City Airport three months earlier.
She sought to conceal this by replacing the passport containing the refusal stamps with a new Brazilian passport, the agency said.
A UK Border Agency spokesman said: "We routinely make checks to ensure that people wanting to visit the UK have not previously tried to circumvent our immigration laws.
"Visitors to the UK must play by the rules. Those who do not are refused entry and sent home."
The spokesman said the same woman had been refused entry at Belfast on 15 January after a baggage search revealed a collection of sexual paraphernalia and details of escort agencies and sex sites.