Sydney (AFP) - Australian film star Nicole Kidman has described 2014 as her toughest ever year, saying the sudden death of her father in Singapore left her family in "so much pain".

In Sydney for the premiere of her new movie Paddington, the Oscar winner said her close-knit family were "hunkering down for Christmas" without her father Antony Kidman.

"You know, I will look back at this year as one of the toughest years our family's ever gone through - I mean, the toughest ever," she told Sydney's Daily Telegraph on Monday.

Antony Kidman, a doctor, died in Singapore in September from a heart attack as he was visiting daughter Antonia and her family.

"I talk about it because I like to keep him alive, in a way," his famous older daughter said.

"Even though you talk about it, you're still in so much pain so, yeah, as a family we're still in a lot of pain. As any family knows when you've had a huge loss, it makes you tighter, you have to also protect each other."

She has also had a bumpy year in her career. The thriller Before I Go To Sleep last month was her worst major opening, with just over US$2 million (S$2.6 million) from a wide release across 1,935 theatres.

In the movie, Kidman plays a woman suffering from chronic amnesia who wakes up every morning with no recollection of her life from her early 20s onwards.

Its weak opening was another disappointment for Kidman after Grace Of Monaco, which was booed at the Cannes film festival earlier this year and savaged by critics.

She said she chose to make Paddington because she wanted something her daughters with singer Keith Urban - Sunday, six, and Faith, three - could enjoy.

"There's nothing like sitting in the premiere of a kids' film, where you hear them all laughing," she said.