Shona McGarty, who plays Walford's Whitney Dean, was recently given a four-week suspension from the BBC soap for "persistently being late".
Albert Square legend Windsor, who quit her famous role as Peggy Mitchell in late 2010, also commented upon an old feud with former co-star Jessie Wallace (Kat Slater) over timekeeping.
Windsor also said on an upcoming edition of The Rob Brydon Show: "It's common knowledge I fell out with Jessie because she was late sometimes. I am sure she has changed now. The business has changed though.
"June Brown, who plays Dot Cotton, says I should provide a masterclass to those starting out.
"Punctuality is important to me. You have to be early and dressed. There were no jeans in my day. When I started off, if you were late you got a ticking off. Then you got a fine and then you were out."
The 74-year-old Carry On star added: "Everybody was late or everybody was talking on their mobiles. I don't like that but the governors are not so strict now. It's a generational thing. It was difficult.
"It was not their fault as it starts at the top. If they are not taught it then it is not there. A lot of the young stars have not had to work their way up."
Watch Barbara Windsor's first ever scene as Peggy below: