Former Australia captain Steve Waugh said South Africa's decision to send a shadow side to New Zealand for a Test tour while their top players take part in a domestic T20 tournament shows the longest format of the game is under threat.

Cricket South Africa (CSA) named seven uncapped players, including skipper Neil Brand, for next month's two-Test tour of New Zealand, which overlaps with the second edition of the SA20 beginning on January 10.

Waugh said the governing International Cricket Council (ICC) and other administrators should step in to protect Test cricket.

"Obviously they don't care," he told the Sydney Morning Herald newspaper.

"If I was New Zealand I wouldn't even play the series. I don't know why they're even playing. Why would you when it shows a lack of respect for New Zealand cricket?

"If the ICC or someone doesn't step in shortly then Test cricket doesn't become Test cricket because you're not testing yourself against the best players."

Reuters has requested comment from the ICC.

The governing body has little role in scheduling bilateral cricket or domestic T20 leagues, which is done by the boards involved. Its chairman, Greg Barclay, previously told the BBC "there's not a lot we can do" about T20 leagues dominating the calendar.

The proliferation of franchise cricket has put the squeeze on bilateral tours in recent years with West Indies in particular struggling to put together their strongest squad.

The CSA cancelled a tour of Australia scheduled early last year to ensure the presence of their top players in the inaugural edition of the SA T20, which is bankrolled by the Indian Premier League franchises.

Australia captain Pat Cummins hoped South Africa's decision did not signal a drift away from Test cricket.

"I know the South African team aren't sending their strongest side, I'm hoping it's just a phase," Cummins told reporters on the eve of the third Test against Pakistan.

"I don't think it's as dramatic decline as it sometimes gets spoken about, but I think there is an issue just with the amount of other cricket out there."

Pakistan captain Shan Masood said the situation could have been avoided by better scheduling.

"All the best sides have to play for the World Test Championship, so it's a pity that South Africa aren't being able to send their full-strength squad," the batter said.

"Hopefully somewhere down the line, schedules can be made in a certain way where we see the strongest elevens playing Test cricket."