Barack Obama touted the economic case for immigration reform on Saturday, suggesting that it would help trim the deficit and boost job creation. In his weekly address, the president said the system overhaul would provide "a big boost" to the US recovery, adding $1.4tn to the economy over the next two decades.

Obama's comments – which were based on a report on the impact of reform that was released on Wednesday – are aimed at putting further pressure on Republicans in the House of Representatives who are resistant to proposals that have already passed the Senate, and which would provide a pathway to citizenship for up to 11 million immigrants now living in the US without documentation.

Conservative opponents to the bill complain that it amounts to an amnesty for law-breakers, without giving a strong enough deterrent to others who may try to enter the US illegally. The Republican House speaker, John Boehner, has said bluntly that he will not allow the Senate bill to be considered on the chamber floor. Some members of the lower house are calling for the bill to be split up and looked at in individual parcels, beginning with greater emphasis on border security.

Obama suggested that after "debating this issue for more than a decade" it was now the time to act, highlighting the economic case for an overhaul of the system

"Immigration reform would make it easier for highly-skilled immigrants and those who study at our colleges and universities to start businesses and create jobs right here in America," he said. "Foreign companies would be more likely to invest here. The demand for goods and services would go up – creating more jobs for American workers."

He added that through additional tax revenue, the overall deficit would be cut by nearly $850bn over the next two decades.

Earlier this week, former president George W Bush entered the fray, calling on Congress to find a "positive resolution" to the issue. Speaking in front of 20 newly-naturalized US citizens at a ceremony in Dallas, Bush said: "The laws governing the immigration system aren't working. The system is broken. We are now in an important debate on reforming those laws, and that's good."

Noting the intervention of his predecessor, Obama said: "If Democrats and Republicans – including President Bush and I – can agree on something, that's a pretty good place to start. Now the House needs to act so I can sign commonsense immigration reform into law."