The 35-year-old defender is desperately searching for a new club in a bid to play regular first-team football ahead of this year's FIFA World Cup.
Neill has been without a club since his short-term deal with J.League outfit Omiya Ardija expired in December.
Perform understands that Neill has been training with Blackburn since arriving in England for Christmas and that there is no timescale on how long he will remain with the club.
The former Blackburn skipper made 227 appearances in all competitions for Rovers and featured in two UEFA Cup campaigns.
He has also played for Millwall, West Ham and Everton in England, but since leaving Galatasaray in 2011, has struggled for regular football.
Short stints at Al Jazira, Al Wasl, Sydney FC and Omiya have followed.
Blackburn sit 10th in the Championship after a 2-1 win at Leeds United on Wednesday.
Neill's Australia will take on defending champions Spain, Netherlands and Chile in Group B at this year's World Cup in Brazil.
