National Police Service spokesman Dennis Janus says the "hacktivist" group Anonymous "tried to take down" the two sites, apparently using a so-called denial of service attack.
Both sites were sporadically online Friday.
Special Report: WikiLeaks
National Prosecutor's Office spokeswoman Desiree Wilhelm says prosecutors are investigating the problems with their website.
Prosecutors said the young hacker police arrested Thursday confessed to participating in attacks by WikiLeaks sympathizers on websites including MasterCard, PayPal and Visa, among others.