Lord Mandelson said there would be investment aimed at creating new jobs
Union leaders and Redcar MP Vera Baird have said they will continue the fight to save the town's Corus plant.
The government has pledged £60m to help the area recover from the loss of 1,700 jobs when the steelworks is partly mothballed at the end of January.
But opponents have said the cash should be spent on saving the plant.
Ms Baird said the money would be received irrespective of the site's future and promised that Corus would not be "written off".
She has given her support to the government package announced by Business Secretary Lord Mandelson on Tuesday, which focused on creating more jobs in the area, specifically in low carbon industries.
However, she said bosses at Corus should continue to try to find new customers in a bid to keep the plant open.
The company had "prematurely cut the steelworks off" when there was profitability in this financial quarter, she added.
Geoff Waterfield, multi-union chairman at Teesside Cast Products, said he believed a large proportion of the £60m had already been earmarked for the area before the plant's closure was announced.
The future of the plant has been in doubt for months
He said: "It is not new money at all. Its just about wrapping and rewrapping things. Its conscience money."
He also claimed Lord Mandelson should have talked to Corus about its financial situation.
He said: "As far as we are concerned the fight goes on. If we have to drag Mandelson to Teesside that's what we are going to have to do."
"The people of Teesside deserve that at least. We deserve to put our case to him."
A spokesman for the Department of Business Innovation and Skills, said: "Peter Mandelson has spent a great deal of time and effort in recent days in putting together a very substantial £60m investment package for Teesside.
"We're not walking away. We're backing Teesside and we're backing its industrial future.
"The government and local agencies will work together to secure the best possible future for Teesside."