The alert level for a bushfire which flared near the Balladonia Roadhouse in Western Australia's south-east has been downgraded, but an important link road between Perth and Adelaide remains closed and is not expected to re-open for at least five days.

Key points: The fire has been burning in bushland since December 20

The fire has been burning in bushland since December 20 It has closed hundreds of kilometres of the Eyre Highway, which links WA to SA

It has closed hundreds of kilometres of the Eyre Highway, which links WA to SA People at the Balladonia Roadhouse are advised to leave if the way is clear

Multiple fires have been burning in the Shire of Dundas, but one reached emergency warning level after flames came close to the remote roadhouse, on the Eyre Highway, about 500 kilometres from the WA-SA border.

More than 400 kilometres of the Eyre Highway is closed between Esperance and Caiguna.

According to Main Roads WA, it is likely to remain closed for a minimum of five days.

"WA Police urge people to stop taking back tracks and unsealed roads to try and avoid road closures which are in place due to the current fire emergency," a statement from Main Roads said.

"The Trans Access Road is closed to all traffic due to bushfires."

The road is an important link for heavy freight trucks travelling between states.

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The fire, which closed the highway, has been burning since December 20, while fires in the nearby Dundas Reserve have been ongoing since Sunday.

The historic mining town of Norseman has been cut off for extended periods over the past fortnight, with about 270,000 hectares destroyed by seven separate fire fronts in the WA Goldfields region.

The Department of Fire and Emergency Services (DFES) has warned homes are not designed or constructed to withstand a fire in today's conditions.

There was a catastrophic fire danger rating in the Goldfields and Eucla region on Thursday.

Temperatures in the Goldfields topped 43.9 degrees Celsius today.

However, in Norseman, near the fire, the temperature only reached 33.3C.