Joe Hockey has ordered the sale of six foreign-owned residential properties and warned there are others in his sights.

The federal treasurer announced on Saturday five investors from four countries have 12 months to sell their half-dozen properties in Sydney and on the outskirts of Brisbane and in Perth.

They ranged from $152,000 to $1.86 million in price.

“Some … purchased property with Foreign Investment Review Board approval, but their circumstances have changed … some have simply broken the rules,” Mr Hockey told reporters in Sydney.

The investors voluntarily came forward following the amnesty the federal government announced in May.

Instead of the normal three-month period, they have a year to sell and will not be referred for criminal prosecution.

But they’re not the only ones to be targeted.

There are 462 other cases under investigation, Mr Hockey revealed.

“I expect more divestment orders will be announced in the not too distant future,” he said.

The treasurer urged others to come forward before the November 30 cut off, saying he will introduce tighter rules into parliament during the next two weeks.

They will include tougher civil penalties, which will see investors lose the capital gain made on the property, 25 per cent of the purchase price or 25 per cent of the market value of the property.

“Australia’s foreign investment policy for residential real estate is designed to increase our housing stock, but those who break the rules and purchase established property illegally are doing so to the detriment of all Australians,” he said.