Murray has been out since July with a hip complaint that hampered him in his Wimbledon exit at the hands of Sam Querrey.
The Scot has been back in training for the last two months but multiple reports claimed he had hit problems before Christmas that could threaten his participation in the Australian Open, which starts on January 15.
Nadal meanwhile finished his season at the ATP World Tour Finals in London in November, but pulled out of that after just one of his scheduled three matches with a knee problem.
The injury saw him cancel a pre-Christmas training camp with Portuguese player Joao Sousa and pull out of the Mubadala World Tennis Championship, which starts tomorrow.
But both players are still said to be fighting fit and aiming to play their first match of the season at next week’s Brisbane International.
“I expect Rafa and Andy to arrive in Brisbane to start the 2018 year,” tournament director Cameron Pearson said on Wednesday night.
“That’s what our communication with both teams of the players has been over the past few days.
“Nothing has really changed.”
Both men have struggled with injury in recent years and Murray in particular has received a number of public warnings to look after his health.
And Wimbledon champion in 1987 Pat Cash recently claimed that Murray could easily have allowed the injuries to force him into retirement for the good of his long-term health.
“It’s a mystery to me why Murray does not just hang his racquet up and enjoy life. He must love it,” Cash told Express Sport.
“You have your long-term health to think of. My hip is gone, my back is gone.
“I can play a bit of doubles but there are very few tennis players who get away with not having to limp around for the latter part of their life.”