Dart, 23, plays the fourth seed on Rod Laver Arena - where she lost 6-0 6-0 to Maria Sharapova in 2019.

"It is a great opportunity to see where my level is," Dart, ranked 173, said.

Dart and Heather Watson, who plays 16th seed Elise Mertens, are the last British players left in the singles.

The match between Dart and Romanian Halep opens the night session on the 15,000-capacity arena at 08:00 GMT.

You can follow Dart's progress on BBC Radio 5 Live Sports Extra's Tennis Breakfast and through the BBC Sport website's live text service.

Watson had to wait until Wednesday to play her opening match, beating Czech Kristyna Pliskova 4-6 6-3 6-1 in blustery conditions. Her second-round match is second on court 22 at about 02:00 GMT.

Dart moved into the second round this year with a gutsy three-set win over Japan's Misaki Doi, going some way to putting that heavy defeat by five-time Grand Slam champion Sharapova behind her.

She was also beaten 6-1 6-1 by Australia's world number one Ashleigh Barty on Centre Court at Wimbledon last July.

"They were both completely different occasions on big courts against big players," Dart told BBC Sport.

"I think I have kept learning from all the experiences I've had over the past year and hopefully I can draw on them and bring that to the match against Halep.

"She's one of the players I particularly look up to. Her athletic ability is pretty incredible and she's a Grand Slam champion for a reason."

British number two Watson, 27, will meet Mertens for the second time in a week after winning their Hobart quarter-final last Thursday.

Another success for the Guernsey player would see her reach the Australian Open third round for the first time since 2013.

"Beating her last week will give me confidence to know I can beat her, especially if it gets close," Watson said.

"I stayed calm last week and stayed there every point. That's what you need to do against a player like her who is very solid."

Meanwhile, 14th seeds Jamie Murray and Neal Skupski begin their men's doubles campaign on court 14, while Joe Salisbury and Cameron Norrie are among other Britons in doubles action.