"She was produced before the magistrate at Negombo who ordered her to be detained at the immigration detention centre before deportation," a police statement said.
The tourist had an image of the Buddha seated on a lotus flower tattooed on her right arm, it said.
It was not immediately clear where the woman, who was not identified, would be deported to.
Sri Lanka is a Buddhist-majority island and the authorities remain sensitive to any disrespect of the religion by foreigners.
Last year, another British tourist was deported for a similar incident.
In 2012, at least three French tourists were handed suspended jail sentences for "inappropriate" behaviour in front of a Buddha statue.