Mitt Romney dismissed as a "stop-gap" measure Barack Obama's move last week to stop the deportation of 800,000 undocumented young people and pledged that he would implement a long-term solution to immigration reform.

Romney was speaking at a convention of National Association of Latino Elected and Appointed Officials on Thursday, one of the biggest Latino conferences in the country, being held in Florida.

He softened his approach on immigration compared with his harsh rhetoric during the Republican primary campaign when he had to appeal to the party base. Romney's speech was largely listened to in silence, suggesting he has a long way to go to win over Latino voters. Polls show he trails Barack Obama among Latinos by at least two-to-one.

The presumptive Republican presidential nominee has been under pressure since Obama's announcement last Friday to say whether or not he would repeal the order stopping the deportation of the 800,000.

Romney did not spell out exactly how he would respond to the order if he was president, other than to say he would replace it with a long-term solution, one he optimistically suggested would be based on bipartisan consensus.

"Some people have asked if I will let stand the president's executive action. The answer is that I will put in place my own long-term solution that will replace and supersede the president's temporary measure," Romney said.

"As president, I won't settle for a stop-gap measure. I will work with Republicans and Democrats to find a long-term solution. I will prioritise measures that strengthen legal immigration and make it easier. And I will address the problem of illegal immigration in a civil but resolute manner. We may not always agree, but when I make a promise to you, I will keep it."

He described immigration reform as a "moral imperative", softer language than during the primary campaign when he was vying with other Republicans for votes from party members, many of whom are hostile towards illegal immigration.

During the primary battles, he advocated self-deportation, pledged to veto the Dream Act, Democratic-backed legislation similar to the order Obama implemented last week, and described opponent Newt Gingrich as being too friendly towards immigrants after Gingrich had said it was unrealistic to expect people who have lived in the US for decades to return home.

In an attempt to court the Latino vote, the Romney campaign team had been tentatively backing in recent weeks a shift by Florida senator Marco Rubio that would have introduced a modest package of reforms to help young people whose parents are illegal immigrants but who have been brought up in the country. Obama's move to grant work visas to young undocumented youths undercut Rubio's effort, which has since been abandoned.

The Latino vote could prove pivotal in what polls suggest will be a tight election in November. In his speech, Romney tacitly acknowledged he had a hard sell trying to court Latinos.

Unable to offer anything significantly new on immigration reform, Romney opted instead to make an appeal on economic grounds, saying that Latinos had suffered disproportionately from unemployment and the drop into poverty.

He also said that Obama, who is to address the conference Friday, had had an opportunity early in his presidency when the Democrats had control of both the Senate and the House to tackle immigration reform but had failed to do so.

"For two years, this president had huge majorities in the House and Senate – he was free to pursue any policy he pleased. But he did nothing to advance a permanent fix for our broken immigration system. Instead, he failed to act until facing a tough re-election and trying to secure your vote," Romney said.

"Last week, the president finally offered a temporary measure that he seems to think will be just enough to get him through the election. After three and a half years of putting every issue from loan guarantees for his donors to cash for clunkers before immigration, now the president has been seized by an overwhelming need to do what he could have done on day one. I think you deserve better."

Setting out the broad parameters of the approach he would take to immigration reform he reiterated that there is a need to secure America's borders by having more guards and extending the fence and to reform the bureaucracy attached to acquiring green cards and visas.

In one of the few passages to win applause, he said he would reallocate green cards to keep families under one roof. Immigrants who achieve advanced degrees should automatically receive green cards.

He also promised to work with states and employers to update the temporary worker visa programme; that people who achieved advance degrees in the US should be allowed to stay; and people who served in the US military should have full citizenship.

"We must also make legal immigration more attractive than illegal immigration, so that people are rewarded for waiting patiently in line. That's why my administration will establish a strong employment verification system so that every business can know with confidence that the people it hires are legally eligible for employment," he said.

Although Romney called for a bipartisan approach to immigration reform, recent attempts have failed. Republicans overwhelmingly opposed the Democrat-backed Dream Act that would have offered a route to work and eventually citizenship for undocumented youths. Republicans in 2007 also blocked a joint move by Republican senator John McCain and one of the Democratic leaders in the Senate, the late Ted Kennedy, for comprehensive immigration reform. Romney was among those opposed.

As well as Romney and Obama, the conference is scheduled to be addressed by Rubio, former Florida governor Jeb Bush and present governor Rick Scott.

There was embarrassment for Romney on Thursday morning when Bloomberg reported that the Romney campaign asked Scott to tone down his comment about improving job figures. According to Bloomberg, the Romney campaign asked Scott to say that the job rate would get better in Romney presidency.Republican governors are torn between trumpeting improvements in job rates in their states and support for Romney's position of scepticism that the job situation is improving.

Bloomberg said a Romney adviser made the request to Scott's staff this week after a drop in May to 8.6% from 8.7% the previous month.A spokesman for Scott denied the Bloomberg story. © Guardian News and Media 2012