Culture Secretary Tessa Jowell has told the Cabinet plans for 17 new casinos, including the UK's first super-casino in Manchester, are "very much alive".
The Lords vote killed off the plans even though MPs supported them
Ms Jowell's defiance came after peers rejected the plans, which had been backed in a separate vote by MPs.
She said on Wednesday she had prepared no "plan B" in case of defeat, and she would now "reflect" on the next step.
Ms Jowell could try to force the plans through against Lords' wishes, or have a complete rethink of the casino plans.
Either way, it seems there will at the very least be a delay of months before the 17 new casinos get the official go ahead.
Manchester representatives remain confident they will get the UK's first super-casino, but main rival Blackpool believes it has been given an opportunity to get the decision on the siting of the super-casino changed.
Peers rejected the plans by 123 votes to 120, killing off the order even though the Commons voted it through despite a rebellion by 18 Labour MPs.
Manchester was recommended by the Casino Advisory Panel in January - much to the shock of frontrunners Blackpool and the Dome in London.
Both houses of Parliament have already passed the Gambling Act - paving the way for the new casinos - into law.
The votes on Wednesday were on so-called secondary legislation, which puts the new laws into effect - in this case allowing Manchester and the 16 other chosen towns and cities to get their new casino licences.
The Lords traditionally do not vote against secondary legislation - the only other occasions since 1945 have been on Rhodesia sanctions and on the Mayor of London's powers.
Lord Strathclyde, Tory leader in the Lords, told BBC Radio 4's Today on Thursday Ms Jowell could have avoided defeat if she had not "pretended" to accept an amendment saying MPs and peers could examine the Manchester decision before any licences were issued.
"It has ended in shambles and chaos almost entirely due to government failure... pretending to accept a Labour amendment and then saying different things in both Houses, using weasel words," he said.
Some peers - including Church of England Bishops - had raised objections to gambling in general, while others were specifically against the order because Blackpool missed out or because MPs did not have the chance to debate the choice of Manchester.
A super-casino complex was recommended for east Manchester
Ms Jowell said after the vote that the government's next move was undecided.
"When you're going to win a vote, you don't have a plan B. You go out to win a vote - and we won in the Commons, and certainly at the beginning of the week it was looking much tighter than it eventually was.
"But given that the Lords have rejected the order, we now obviously have to consider both their amendment and the various options that are open to us."
Manchester Blackley MP Graham Stringer said it had become a constitutional issue between the two Houses.
"What we can't have is an unelected House trying to effectively reopen the debate on the Gambling Act."
He added: "The House of Commons is elected and when there is a conflict one has to be dominant and that must be the elected House."
Mr Stringer said political opportunism by the Conservatives had "hijacked" the casino plans.
The Tories were initially supportive of the plans, but "as soon as they saw there were some Labour backbenchers in the Commons who were likely to rebel they completely changed their position".
However, Lord Strathclyde dismissed his criticism, saying the Tories based their stance on a report from a House of Lords scrutiny committee which suggested the panel which chose Manchester had misinterpreted its brief.
He also disagreed about the constitutional issue: "There were so many different people voting from so many different ways.
"The mood in the House of Lords was so shocked by the line the government was taking that I don't think there is a constitutional matter at all."
The Lords vote was criticised by Greater Manchester Chamber of Commerce chief executive Angie Robinson.
She said: "This is complete madness and we are bitterly disappointed at this absolutely outrageous decision.
"The super-casino would have brought much-needed jobs and investment to one of the most deprived areas in the country."
Alan Cavill, of Blackpool Council, said the vote could give the town, which was the original favourite to get the super-casino, a second chance. The former Millennium Dome in London was also among the front-runners.