Sierra Leone meth 'mules' deny knowledge

Two women who were found with kilograms of methylamphetamine hidden inside their luggage after flying from Sierra Leone to Australia claim they didn't know the drugs were there.

Matafa Fofana, 21, and Rosaline Koroma, 29, had almost 9kg of low-grade meth, equating to 4.83kg of pure meth, concealed in the lining of their suitcases when they arrived in Perth in May last year.

The District Court of WA heard on Monday that the pair, who lived together in Melbourne, were of limited financial means and sometimes overdrew their bank accounts.

But records showed they suddenly discussed plans to go to Sierra Leone "for business", then bought relatively expensive domestic and international flights soon before their departure.

"It seems to have been a fairly last-minute decision," prosecutor Thomas Offer told the jury.

While the women claimed when they returned to Perth their trip was for Sierra Leone's independence day, they were actually in Nigeria on that date.

They didn't initially admit going to Nigeria when later questioned, Mr Offer said.

The trial continues.