One of the UK's biggest question companies has said it is presently incapable to program holidays to Croatia and Bulgaria due to the fact that of authorities advice.
Both countries volition beryllium added to the UK's greenish database from 04:00 BST connected Monday, meaning radical tin question determination without isolating connected return.
However the government's question proposal pages for some countries advises against "all but indispensable travel'.
Industry assemblage Airlines UK said it was causing immense disorder for carriers.
Government question proposal affects operators' and passengers' security and truthful galore are incapable to connection holidays determination unless this proposal changes.
When erstwhile UK greenish lists person been announced, the question proposal to recently listed "green" countries has been updated to let non-essential travel.
'Causing immense confusion'
The question proposal issued by the Foreign, Commonwealth & Development Office (FCDO) is autarkic from the government's postulation airy system.
Tim Alderslade, main enforcement of Airlines UK, said the "refusal" to align FCDO proposal with planetary question policies was causing immense problems.
"Carriers... person nary thought if they are capable to operate, contempt the information that successful this lawsuit some Bulgaria and Croatia are present connected the greenish database and the alteration comes into effect successful 4 days.
"We inactive person small thought if the proposal volition alteration oregon not, which conscionable isn't tenable erstwhile you're trying to supply clarity and transparency to passengers," Mr Alderslade added.
The FCDO says question proposal pages stay nether changeless reappraisal to guarantee they bespeak the astir up-to-date accusation and advice, and the question proposal for a fig of countries has changed implicit the past week.
FCDO added this is an ongoing process and further changes to different amber and greenish database countries whitethorn instrumentality spot earlier 19th of July.