Four women who were alleged victims of human trafficking were forced into prostitution in Ireland after undergoing a voodoo ceremony in their native Nigeria, a trial has heard.

Details of what State prosecution lawyers have called a "tragic" case of exploitation were heard at the opening day of the trial at Mullingar Circuit Criminal Court of two women accused of involvement in human trafficking, prostitution and money laundering.

A male associate is also charged with various money laundering and prostitution offences, while all three defendants face a single charge of committing an offence for a criminal organisation.

The accused are three Nigerian nationals, Alicia Edosa, 44, of The Harbour, Market Point, Mullingar, and Edith Enoghaghase, 31, and Omonuwa Desmond Osaighbovo, 30, both of Meeting House Lane, Mullingar.

Ms Edosa is charged with four counts of human trafficking, one count of prostitution and 36 counts of money laundering on various dates between September 2016 and June 2018.

Ms Enoghaghase is accused of two counts of human trafficking, one count of prostitution and eight counts of money laundering while Mr Osaighbovo is charged with one prostitution offence and eight counts of money laundering.

All three defendants have pleaded not guilty to a total of 63 separate charges.

In her opening remarks, counsel for the DPP, Fiona Murphy SC, said four young women from a deprived background in Nigeria had been abused in an underhand way by the three accused.

Ms Murphy told the jury it was a tragic case of exploitation by people from Nigeria searching for a better life.

She said evidence would be heard that the women believed they were coming to Ireland to have an opportunity to engage in legitimate work.

Ms Murphy said all four women took part in a voodoo ceremony before leaving Nigeria for Ireland in which they took an oath to people arranging their journey.

On arriving in Ireland, she said the women were told they would have to repay the accused what she described as "extortionate amounts" by engaging in prostitution.

"Four vulnerable women were exploited and had no alternative but to submit to the rules," said Ms Murphy.

She said the women were used in "a most egregious fashion" by having to travel to various locations around Ireland to engage in prostitution from their base in Mullingar.

She said they also had to pay cash or lodge money to the accounts of the three accused.

The allegations came to light after the women were able to extricate themselves at various stages and report matters to gardaí.

The trial before Judge Francis Comerford and a jury of ten men and two women is expected to last at least three weeks.