Smith, 33, scored 17 goals in 91 games in three seasons at the Den before joining Salford City in 2022.

"Season on season they seem to be getting closer. Rowett has taken them to the next level," Smith said.

"They look like a really, really strong outfit again this season. You expect them to be at the top end of the table now."

Millwall were beaten 3-2 at home on Saturday by Norwich, who climbed above their hosts into the final play-off position.

It was the first time Rowett's Lions have lost at the Den in the Championship since a 2-0 reverse in September to another of Smith's old clubs, Queens Park Rangers.

A home defeat at a crucial moment to a promotion rival has not given Smith any reason to doubt the 49-year-old former Stoke City and Birmingham City boss.

"I think he's one of the best managers in the division, I've worked under a lot of different managers and he's as good as they come," Smith told BBC Radio London.

"He's provided a real level of consistency to that club. On a personal level he's a really good bloke, I really enjoyed working for him. I know the lads really enjoy working for him - he's a really humble, nice guy that you can talk to - very respectful.

"He's been so consistent at all his previous clubs so it's no surprise to me that they're fighting for promotion."

Former Leeds and Fulham striker, Smith, was signed by Millwall's record-goalscorer Neil Harris in July 2019 from Queens Park Rangers.

A slow start to the following season led to Rowett replacing Harris, who stood down two months into the new season after a seven-match winless run.

"He's come off the back of the excellent work that Neil Harris did at the club in stabilising them as a solid Championship side," Smith said.

"He never gets too high with the highs or low with the lows, and he'll trust his process and monitoring the lads and looking after them where they need looking after to get the best out of them.

"It's great to see them battling at the top end of the table and mounting a really good push. For the lads and for the manager I really hope they can do it."

Millwall's next fixture is away to Reading on 11 March.