The Tigers are top of Super League and in the Challenge Cup quarter-finals.
However, Brian Noble says it is his record over the past three years that makes Powell the main candidate for the vacant Lions job.
"He'd be my man, absolutely," Noble told the 5 live Rugby League podcast.
"It's not just this year. Those that have watched his team last year and previous years understand his philosophy on football."
The revival of the Great Britain and Irish Lions was confirmed last week with the news they would tour Australia and New Zealand in 2019.
It will be their first tour since Noble took the Lions down under in 2006 - a trip that included a victory over Australia in Sydney.
"The Lions is a certain brand, isn't it?" said Noble. "We have this constant argument about a Super League style and an NRL style.
"What we're seeing from a Super League style in Castleford in particular is that they're scoring a lot of points and playing a lot of football.
"It's not just made up, there's a system and a structure and a strategy behind it."
Media playback is not supported on this device
England's Australian coach Wayne Bennett is also likely to be a prime candidate for the Great Britain post, especially if he leads England to World Cup success this year.
But Noble wants the Rugby Football League to go home-grown when the iconic Lions tour again.
"I'm fully supportive of Wayne Bennett now, because he's got the [England] job," added Noble. "I'm a proud Englishman, and I want England to do well in the World Cup.
"I understand the move for Bennett, and I understand what he would bring to the table.
"However, in 2019 I'd really like to believe we could take a British identity down under, led by Daryl, but have some other English coaches with him."
Castleford coach Daryl Powell should lead the Great Britain and Irish Lions to Australia and New Zealand in 2019, according to the man who last took the team down under.