Traynor was known as a "fixer" in the Irish criminal underworld and as the man to go to for information and money.
The 62-year-old has been on the run from British police for 18 years and now faces extradition to Britain to finish a prison sentence for a multi-million pound fraud.
It is understood he was arrested in Amstelveen, near Amsterdam, after he produced a false ID when trying to hire out a car on Monday, August 23.
Traynor now faces being extradited to the UK to finish a term for fraud which involved stolen treasury bonds worth an estimated €4.8 million.
He had only served 12 months of a seven-year sentence when he failed to return from a weekend's compassionate leave that was granted to him by British authorities, fleeing at the time to Ireland.
Traynor's arrest is believed to have been masterminded by Britain's Serious Organised Crime Agency who were working with Dutch police.
"Convicted fraudster John Traynor, aged 62, has been arrested in the Amstelveen area of the Netherlands," the British police said in a statement.
"He is now awaiting extradition to the UK to serve the remainder of his sentence."
In a planned sting operation in 1990, police caught Traynor as he directed a courier to take £1 million from a Swiss bank and was remanded in custody until October 1991, when he was convicted for fraud.
He was granted compassionate leave in 1992 to visit his wife and four children but never returned to the UK. Traynor is expected to appear in court in the coming days when the extradition process will begin. Traynor was suspected of supplying information to John Gilligan's gang who carried out the murder of the top journalist.
Traynor was an underworld source for Veronica Guerin and she kept in regular contact with him. Veronica Guerin was shot six times by a pillion passenger on a motorbike on the Naas Road, co Kildare in June 1996.