School readiness is a contested and emotional term..
"Today there are thousands of early childhood development workers in this country who live off inadequate stipends and who suffer appalling working conditions," Vavi said.
He was speaking a SA Democratic Teachers Union (Sadtu) conference in East London.
He said early childhood development workers were largely invisible and unorganised.
"They live in a twilight world of vulnerability, at the same time as providing a critical role in preparing young children for formal school.
"I want to seriously challenge you to think about reaching out to early childhood development workers as a highly exploited group of vulnerable workers," he said.
Vavi said educators needed to play a leading role in the union's campaign for a radical economic transformation.
"We need a transformed alliance, not the one which only comes to life on the eve of elections and immediately thereafter allows government to dictate policy and direction of the revolution alone," he said.