Construction could start on another rail crossing of Sydney Harbour this decade after Transport Minister Gladys Berejiklian said she would press Premier Mike Baird to bring forward the project.

In her first extensive interview since she decided not to challenge Mr Baird for the premiership, Ms Berejiklian also said she ''selfishly'' chose to remain in transport rather than take on another job because she wanted to see the fruits of her three years in the position.

"I considered all my options ... and I came to the conclusion that Mike was the best one to do the job": Transport Minister Gladys Berejiklian with Premier Mike Baird. Credit:Anthony Johnson

With support in the moderate wing of the Liberal Party, Ms Berejiklian was considered a favourite to replace Barry O'Farrell after he resigned last Wednesday over misleading a corruption inquiry.

But she said she chose not to challenge Mr Baird after deciding he was the best person for the job.