Tighter and more expensive visa regulations for Australians travelling to the UK could have a long-term impact on the close relationship between the two countries, according to officials and members of the British Prime Minister's own party.

Key points: Raft of visa changes to impact Australians working in the UK

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Income test for those applying for permanent residency MP warns changes could affect Australia-UK relations

From April 6, Australians staying longer than six months in the UK will have to pay $400 (200 GBP) for the 'free' National Health Service (NHS).

Australians wanting to consider permanent residency in the UK will have to be earning a minimum of $70,000 (35,000 GBP) to be permitted to stay.

The new laws, announced several years ago, come into effect in a matter of weeks and have faced a fresh round of criticism.

But new recommendations from the British Migration Advisory Committee (MAC) have sparked even more outrage with warnings from one official that Britain is sleepwalking into a situation where the once tight relationship with Australia will be permanently damaged.

The committee has recommended to the UK Home Office that Australians on Tier 2 working visas will face a $2,000 (1,000 GBP) annual fee. It does not specify if the employee or the company should be encouraged to pick up the bill.

It also recommends companies wanting to employ non-EU workers will have to guarantee they will be paying them a minimum of $60,000 (30,000 GBP).

Conservative MP Andrew Rosindell, who is also a member of the Commons Foreign Affairs Select Committee, has sounded the alarm, believing it will discourage Australians from coming to the UK.

"I think it is wholly wrong that we should allow that relationship to be harmed or watered down in any way and I'd like to see our government completely relook at rebuilding that relationship and making it ever strong," he told the ABC.

Minimum salary 'unreasonable' in many fields

Genevieve Rogis is an Australian student who is hoping to remain in the UK permanently.

She is one of many Australians critical of the new rules as well as the recommendations that could see visas being tightened even further.

"It doesn't take into account that many people work in jobs that is a completely unreasonable salary," she said.

"They're never going to earn that much money."

The National Association of Head Teachers is warning that the British school system cannot afford to lose any Australian teachers.

"We know that every year the Government is registering 500 Australian teachers who want to work in this country and we don't want to reduce that pool," union spokeswoman Valentine Mulholland said.

The union is lobbying the UK Government to allow an exemption for Australian teachers.

UK Prime Minister David Cameron has promised to substantially decrease non-EU migration, but critics say Australians should not be caught up in what has become a bitter political fight over immigration.

Australians are among those given the most number of work visas in Britain, although most of them are on the two-year "youth mobility" scheme, which the British government has promised to keep in place.

Australian Peter Dore-Smith who owns Kaffeine cafe in London says it is disappointing more Australians aren't allowed to stay.

"I've had so many young people coming and working for me from Australia, 18 and 19 years-old," he said.

"You just see them grow so much. And then they're forced to leave and it's a shame."

He predicts businesses will feel the crunch from these new rules.

"To stop that happening is limiting the businesses that are struggling and limiting the people trying to put back into the economy. Why would you limit that? You want to grow," he said.

An online petition is aiming to get 100,000 signatures to force a debate in the British parliament over the rules.