Tony Woodley, Unite joint general secretary, added: 'Workers and their families will march to send a clear message to the management of Corus and the government, this community must not be forgotten.'
Community leaders warned that job losses would 'dramatically' increase poverty in the local Teesside region, named for the Tees river.
'The march to Save our Steel should really focus minds on what's at stake here,' union official Richard Green said.
'With the plight of children becoming a serious problem in our community, it's time to recognise that the best answer to the threat of children living in poverty is to ensure that their parents have access to sustainable long-term employment.'
According to the Campaign to End Child Poverty, Teesside faces child poverty rates above the national average. Throughout the Tees Valley three in four children are classed as experiencing severe financial hardship either in a low income family or a non-working family.
'Teesside Cast Products (TCP) is one of the main employers in the area and part of the backbone of British manufacturing. Support for TCP now will cost the government far less over the long term than trying to rebuild the local economy if TCP is forced to close,' Green said.