Two police officers have been injured in an explosion at a farm in Victoria’s west.

The blast has closed the Hamilton Highway at Derrinallum and a 6km exclusion zone has been set up around the site.

The male officers, both in their 30s, had been negotiating with a man who was threatening to harm himself when the blast occurred about 1.30am.

One of the officers received head injuries and was flown to Melbourne’s Alfred Hospital.

He is in a serious but stable condition.

The other officer suffered bruising, cuts and abrasions and was taken by ambulance to Geelong Hospital.

Police say there have been further explosions and the scene remains unsafe.

Officers have so far been unable to locate the man involved in the incident.