Armed police have been deployed at the St Fergus gas terminal near Peterhead to bolster security.
Armed officers have been deployed at Aberdeenshire sites
Several armed officers are also at gas compressor facilities at Garlogie, also in Aberdeenshire.
The precautions at the facilities have been increased from Tuesday with the introduction of the Ministry of Defence (MoD) police.
The Home Office has insisted the heightened security is not the result of a specific terrorist threat.
The officers, who have the authority to shoot to kill, are stationed at the bases around the clock.
Extra MoD police have been drafted in to guard what is deemed "critical infrastructure" as part of a major review of the UK's security strategy.
SNP leader and Banff and Buchan MP, Alex Salmond, said: "This is a sensible precaution especially considering the current international environment."
Aberdeen-based terrorism expert David Capitanchik told the BBC Scotland news website last year that there was no room for complacency.
He warned before the fifth anniversary of the 9/11 twin towers attack that energy, royal and RAF connections meant the north east of Scotland had to remain alert.
The St Fergus terminal is a major energy centre
Aberdeen, as well as Peterhead, is a major hub of the oil and gas industry, the Royal Family often stay at Balmoral and Birkhall in Royal Deeside, and the RAF has bases at Lossiemouth and Kinloss.
Mr Capitanchik said: "We cannot afford to be complacent in this part of the world - we have to keep up the same level of security as anywhere else.
"You cannot afford to take the view that because we live in a remote area a terror group will not decide it's a place to attack. They are looking for soft targets.
"We do have certain targets that are part of the critical national infrastructure."