Corus is struggling with massive debts
Welsh plants have escaped the worst job losses in the latest round of cutbacks at Corus, which announced 1,150 cuts on Tuesday.
However, more than 100 jobs are to be lost at the Llanwern steelworks in south east Wales, as the firm streamlines its production.
The Anglo-Dutch firm is battling to fight losses of more than £400m - in 2001, more than 2,000 Welsh jobs went as part of 6,000 cuts across the UK.
Meanwhile, up to 35 extra jobs will be created at Port Talbot - where the company said it would now concentrate a large part of its UK output.
A company spokesman said the cuts, which were "regrettable", are due to be made between 2004 and 2005, although workers wishing to fill the new vacancies at Port Talbot would be given serious consideration.
Elsewhere in Wales, Corus's other plants are expected to remain unaffected.
With steelmaking for flat products in the UK concentrated at Port Talbot, the mills and coating line at Llanwern will be supplied from there
Sir Brian Moffat, Corus chairman
"It's going to put Port Talbot on the international map and make it a world class player, able to compete with the best," said the spokesman.
"Job reductions at Llanwern are regrettable - we will deal with them very sensitively," he added.
Corus said that, subject to its financing proposals, it plans to increase the production of steel slabs' at Port Talbot by 25% to 4.7m tons a year.
The move will make the plant self-sufficient in producing low-cost, in-house steel slabs.
A spokesman explained that the investment involves "unlocking the full potential of Blast Furnace Number Five, installing a third casting machine and raising steel-making capacity commensurate with that".
On Monday, Corus announced 200 jobs would be created at the Shotton steelworks in north Wales - two years after 400 people were made redundant.
The plant worst affected by Tuesday's announcement will be Stocksbridge near Rotherham, where more than 800 jobs will go and steel production will cease.
The future of a further 2,200 workers on Teesside remains in doubt.
Corus has losses of over £400m
Sir Brian Moffat, who is resigning from his post as chairman next month, explained how Corus would be restructured.
"Steelmaking for flat products should be concentrated at Port Talbot in south Wales, steelmaking for long products at Scunthorpe in north Lincolnshire and steelmaking for engineering steels at Rotherham in South Yorkshire," he said.
"Once the necessary investment has been carried out at Port Talbot and Scunthorpe, steel production from Teesside will not be required for the group's internal demand.
Welsh Secretary Peter Hain said the future of Welsh steel-making had been secured.
"This is a big relief and good news for south Wales that Port Talbot will now become the primary steel-making plant for the UK," he said.
"Although it is regrettable that there will be an overall reduction of 1,000 jobs in the UK, I am relieved and delighted at the confidence
shown in Port Talbot and Llanwern," he added.