US President Donald Trump has called for a "merit-based immigration system" similar to those of Canada and Australia in place of the current "outdated" programme.

Such a system is likely to give Indians an edge because large numbers of the diaspora has high education and skill levels.

Delivering his State of the Union Address to a joint session of Congress on Tuesday night, the Republican President said: "I believe that real and positive immigration reform is possible, as long as we focus on the following goals: to improve jobs and wages for Americans, to strengthen our nation's security, and to restore respect for our laws."

"Nations around the world such as Canada, Australia and many others, have a merit-based immigration system," he added.

"It is a basic principle that those seeking to enter a country ought to be able to support themselves financially."

By not following such a system, he said the US was "straining the very public resources that our poorest citizens rely upon".

"Switching away from this current system of lower-skilled immigration, and instead adopting a merit-based system, will have many benefits: it will save countless dollars, raise workers' wages, and help struggling families — including immigrants — enter the middle class," he said.

Trump did not mention those in the US on temporary work visas for skilled workers and professionals known as H-1B. The vast majority of those holding the H-1B visas are Indians.

In earlier speeches the President had said that he would root out abuses in that visa category and restrict them if they were to throw Americans out of work.

India — as well as technology companies — have expressed concern over the possibility of limiting H1-B visas.

Trump appealed to the Democrats for bipartisan support for immigration reform.

"If we are guided by the well-being of American citizens then I believe Republicans and Democrats can work together to achieve an outcome that has eluded our country for decades," he said.

Many Democrats are likely to oppose a merit-based immigration system as they would assert that it would not help the poor and the unskilled immigrate to the US and discriminate against immigrants from Latin American countries whom the party counts as a key part of its base.

Trump did not spell out how the merit-based system would work.

In Canada, applicants for immigration are given points for different qualifications like education, skill levels, language and family ties. They would have to meet a minimum score to be allowed to immigrate.

Currently the US immigration system restricts the number of people who can immigrate from each country to seven per cent of the total number allowed in except for immediate relatives of citizens.

This has led to several years' wait for Indians to get their green cards. There is also a limit of 140,000 on employment-based green cards.

How the reform would ultimately affect Indians could ultimately depend on how country limits and the number of employment visas are handled and also on the retention of the immigration privileges for brothers and sisters of citizens and their families.

Keeping his election promises, Trump maintained a hardline on illegal immigration, exclusion of people from countries where it is difficult to vet applicants for visas to travel to the US, and building a wall along the border with Mexico.

Taking aim against critics of the first phase of his enforcement of immigration laws that targets criminal illegal immigrants, he spoke about the victims of crimes by illegal immigrants who "have been ignored by our media, and silenced by special interests".

Families of a student and law enforcement officers killed by illegal immigrants were in the audience and Trump hailed them amid a standing ovation by most members of Congress.

He said the construction of a "great wall" along the southern border will start soon.

As for the ban on travel to the US by citizens from seven countries that has been thrown out by courts, the President said a system with improved vetting procedures would be introduced shortly.

"We cannot allow a beachhead of terrorism to form inside America — we cannot allow our nation to become a sanctuary for extremists."

Trump listed the terror attacks carried in the US by foreigners to buttress his claim for tighter scrutiny. Although those attackers did not come from the seven countries.