Australia's top cricketers face being locked out unless a new memorandum of understanding (MoU) is struck between Cricket Australia (CA) and the Australian Cricketers' Association (ACA), with the current agreement set to expire on June 30.
ACA president Dyer said players and Cricket Australia remained "a long way apart" on basic issues and the union was preparing its members for unemployment.
"It is extremely likely that as of July 1 we'll be jumping over the cliff together," Dyer told local media on Tuesday.
"The fundamentals of the deal are nowhere near to being resolved.
"Over 200 of Australia's most senior cricketers are unemployed as of the 1st of July.
"We will be assisting in whatever way we possibly can in that but they're unemployed."
At the heart of the dispute is a long-standing agreement that gives the players a fixed percentage of the revenue of the game, a deal which CA says prevents them from sufficiently investing in the grassroots.
CA offered a revised deal on Friday but the union quickly rejected it.
Unless the impasse ends, the upcoming Australia 'A' tour of South Africa, a two-Test series in Bangladesh and a limited-overs tour of India are under threat, with the Ashes also looming at the end of the year.
CA has declined to comment on the negotiations but said in announcing its revised offer last week that it was "100 percent committed" to resolving the MoU by the deadline.
Former Australia Test opener Ed Cowan, who is contracted for New South Wales state, said players remained unified and resolute in their demands.
It has cast doubt on Steve Smith's Test side boarding the plane for Bangladesh for the Test series starting August 27.
"The next line in the sand is probably the tour of Bangladesh, do the players go on that late August?" said Cowan.
"My gut feeling is probably hit and miss for security reasons (and) MoU reasons."
The ACA has already made moves to prepare for a lockout, setting up a business to manage and market players' intellectual property.