The Turnbull government has announced a further crackdown on foreign buyers of prime agricultural farmland, saying Australians must be given the chance to buy the land first and that foreign investors can only buy the land for residential development if they begin developing within five years.

The government has also formalised restrictions on foreign investment in Australia’s energy infrastructure, such as electricity wires, so foreigners know their bids may be officially declined on “national interest” grounds.

The treasurer, Scott Morrison, made the announcement on Thursday amid growing concerns over interference in the Australian political system by Beijing and numerous controversies surrounding Chinese investment in Australia’s energy infrastructure and farmland.

From now on, sellers of Australian agricultural land must officially advertise and market the holdings to Australians first.

Foreign investors will have to demonstrate the agricultural land they intend to buy has been part of a public sales process, and marketed widely to potential domestic bidders for a minimum of 30 days, and that Australian bidders have had an opportunity to take part in the sale process.

All acquisitions of agricultural land by foreign investors for residential development will also now require development to begin within a five-year period to prevent land banking (a condition already applying to acquisitions of vacant land).

“We welcome foreign investment in Australian agricultural land where it is not contrary to the national interest,” Morrison said on Thursday. “Our foreign investment rules facilitate investment while making sure Australia’s national interest is protected. This includes ensuring adequate opportunity for Australians to invest in Australian land.”

He said the new rules build on previous initiatives, such as the agricultural land register and reducing the screening threshold for foreign purchases of agricultural land from $252m to $15m.

Morrison said sales of critical energy infrastructure were already scrutinised by the Foreign Investment Review Board (FIRB) but future transactions would be officially scrutinised on a case-by-case basis by taking into account the cumulative level of ownership within a sector, the need for diversity of ownership and the asset’s critical importance.

It means foreigners now know their bids for Australia’s critical energy infrastructure may be officially declined on national security or national interest grounds.

“Where required, ownership restrictions will be flagged to the market as early as possible in the sale process,” Morrison said. “The government is committed to an open foreign investment regime that strikes the right balance in managing national security risks, while promoting job opportunities and enabling economic growth.

“With electricity distribution assets, the stakes are higher and Australians expect additional foreign investment protections in place.

“Today’s announcement gives clarity to potential investors and avoids surprises for state governments and private sellers of electricity transmission, distribution and generation assets.”

Morrison said applications for ownership of critical energy infrastructure would be reviewed by FIRB, with help from the Critical Infrastructure Centre.

He said the centre would provide better advice to FIRB once it could draw on ownership information captured in the proposed critical infrastructure assets register, contained in the Critical Infrastructure Bill 2017, which is currently before parliament.

The shadow treasurer, Chris Bowen, said Labor would look at the details of the energy assets announcement but said they did not appear to be “a substantive change” to powers available under FIRB rules.

In 2016, Morrison rejected a Chinese bid to lease New South Wales electricity assets and also blocked the sale of Australia’s largest landholder S Kidman & Co to a majority Chinese-owned consortium.

The Chinese embassy has been contacted for comment.