Australian actress Rachel Griffiths has been nominated for an Emmy award for her work on the TV drama Brothers and Sisters.

Griffiths joins other top actresses aged in their late 30s and over who dominate this year's Emmy nominations.

Although teenagers and 20-somethings are the target demographic for many TV shows, only one actress nominated for an Emmy on Thursday is in her 20s: 24-year-old Ugly Betty star America Ferrera, for lead actress in a comedy series.

Almost all of this year's nominated actresses are 40-plus, with many in their 50s and some in their 60s.

Griffiths, 39, whose character Sarah heads the family business in Brothers and Sisters, credited TV's focus on strong characters with creating better roles for older actors.

"People want to tune in to complex, interesting, quirky, unexpected, flawed characters, and that's across the board, female and male," said Griffiths, nominated in the supporting actress category that includes women in their late 30s and early 60s.

"But the more mature actors maybe have an edge on confidence in terms of really owning those characters. I think as a young woman it's considerably more difficult to amplify your unusual parts in quite the same way."

At 42, The Closer star Kyra Sedgwick is the youngest nominee for lead actress in a drama series.

At 44, Laura Linney, who played Abigail Adams in John Adams, is the baby of the bunch nominated for lead actress in a mini-series or movie.

"There's always been this myth that in Hollywood women can't make it after a certain age and it's just not true anymore," Sedgwick said.

"I just think that we're tired of seeing just these young bodies and young people. They're lovely and wonderful but they only have a certain level of depth because they've only been on the planet a certain amount of years."

Television has long been more accepting of women over 40, said Julia Louis-Dreyfus, 47, nominated for lead actress in a comedy series for The New Adventures of Old Christine.

That's why the roles are so compelling and potentially award winning, said Anjelica Huston, 57, nominated for her guest starring role on Medium.

"There are a lot of women out there watching television and they still remain a guiding force for television," she said. "The nominees are all really strong women doing well in their businesses and it's nice to know that there's a healthy work life for us."

But the same can't be said for feature films, she added.

"In a world where the poster of Mamma Mia doesn't include Meryl Streep," she said, "it's definitely a situation in which one is gratified to be noticed."