Western Australian police have seized more than 1kg of gold, alleged to have been unlawfully taken from an established mining lease just outside Kalgoorlie.

Detectives are likely to charge four people over the alleged taking of the gold, worth around $A50,000.

Gold Stealing Detection Unit officer-in-charge Bill Little said the gold was taken from the lease on June 4.

Police received information several days later when those involved allegedly attempted to sell it.

Little said complaints of illegal mining and trespass onto gold mining leases were keeping his unit particularly busy, particularly after the recent spike in the gold price.

The gold price reached as high as $A1845 an ounce last week, an all-time high.

"What we're trying to say to people who are out here prospecting is please make sure you're following the rules," he said.

“Don't go where you shouldn't go, because we are actively investigating complaints, as is the Department of Mines and Petroleum.”

The Department of Mines and Petroleum Minerals Titles Division has warned prospectors to only work in areas for which they have a right.

DMP Investigation Services Branch lead investigator Kevin Mancini urged people to report suspected illegal activity.

Helpful information to report includes the time, date and precise location of the activity, details of people or vehicles seen, specific tenement numbers if possible, and photographs or video of the activity.

The GSDU investigates criminal activity and allegations of theft during the gold production process in the state, and also conducts security training at mine sites.
 
The unit consists of only a small number of detectives but is the oldest specialist police service in WA, established in 1907 after a royal commission in 1906.

One of its higher profile cases was in 2011 when two men pleaded guilty to stealing almost $95,000 in gold from Jundee and were sentenced to 12 months jail.