Fierce forest fires which have raged in northern Sweden for nearly a week should soon be extinguished a local fire and rescue service official said on Wednesday.

"We now have the blazes under control" Lennart Juhlin said in a press statement though a fire brigade official said the situation could again change for the worse.

A total of 100 firemen backed by seven helicopters were still battling the larger of two blazes covering an area of about 1000 hectares some 350 kilometres north of Stockholm.

"Even if we are getting there we can't say we have aaaa control of the situation" fire brigade official Ulf Andersson told AFP. "A lot depends on the winds and if they start blowing the fire could flare up again."

The second blaze covering an area of about 100 hectares was completely under control with only a few hoses being employed to extinguish it totally.

However Andersson warned that the whole area was very dry and the risk of more fires remained acute.