The Tigers pair have both garnered rave reviews for their efforts in lifting the relegation favourites to 11th place in the Barclays Premier League.
Centre-half Davies and midfielder Huddlestone have each been championed as potential England call-ups during the season, but national boss Roy Hodgson has remained unmoved and overlooked the duo once again when naming an expanded 30-man squad to take on Denmark.
Bruce admitted his surprise that Cardiff's Steven Caulker had been preferred to Davies this time, but has told his charges not to give up hope.
"In my experience there's always one that comes from nowhere and goes to the World Cup and it could be one of ours," he said.
"For Curtis and Tom to be even linked with it is good for them and they've got to stick with it and keep performing, then who knows?
"You've just got to keep at it but it's all about one person and that's Roy Hodgson.
"Management's all about opinions. In my opinion, Curtis would be in there above Caulker but I've worked with Curtis for the last six months, so I know what he brings to the table.
"Consistency-wise he's arguably been our best player, week in and week out. He can only keep doing that. There might be more twists and turns
"They've just got to stick at it and keep knocking on the door."
While Huddlestone was capped four times by England during his time at Tottenham, the closest Davies came was an appearance on the bench under Fabio Capello.
At almost 29, time would appear to be running out on his international career - a feeling Bruce knows all too well, having never played for England despite his success as Manchester United captain.
"People debate who the best player never to play for England was. A lot say Billy Bonds, some people, if they're Manchester United fans, might say me," said Bruce, before jokingly adding: "If he (Davies) is going to be mentioned alongside me, he better get a move on!"
Bruce was offered a chance to wear the Three Lions late in his playing days but rejected the apparent 'sympathy cap'.
"I had the chance, Terry Venables rang me. I think we were playing Nigeria at Wembley and they must have been struggling," said Bruce.
"He rang me and said 'I want to give you a cap', but I declined.
"My best mate Bryan Robson was Terry's assistant and he was desperate for me to get a cap but I turned it down.
"I was 35, 36 and said 'I'm sorry would rather not have had an international career than just have a sympathy cap'."