Jeremy Corbyn has said he is "ready to fight another election campaign" as he vowed to lead Britain out of the EU.
The Labour leader said his party would "absolutely" ensure Brexit occurs if they secured power, with a focus on negotiating tariff-free access as part of a "jobs-first Brexit".
Labour won 262 seats in the General Election, up from the 232 secured by Ed Miliband in 2015, but the Conservatives remain the largest party in Parliament.
Mr Corbyn told ITV News that that would put up their own programme of legislation for a vote of approval in Parliament.
"We're going to put up a substantial amendment to the Queen's Speech which will outline what we fought the election on and parliament will have a choice," he said.
The Queen's Speech is put forward by the Government at the start of a term in parliament and sets out their main proposed policies and legislation.
When asked on The Andrew Marr Show if there will be another general election this year, Mr Corbyn said: "I think it's quite possible there'll be an election later this year or early next year, and that might be a good thing because we cannot go on with a period of great instability.
"We have a programme, we have support and we're ready to fight another election campaign as soon as may be, because we want to be able to serve the people of this country on the agenda we put forward, which is transformative and has gained amazing levels of support."
Mr Corbyn believes that without an outright majority Mrs May's position is vulnerable and he intends to oppose the Queen's Speech and table a "substantial amendment" in an attempt to bring down her administration.
He said: "We're going to put down a substantial amendment to the Queen's Speech which will contain within it the main points of our manifesto, and so we'll invite the House to consider all the issues we put forward which I've mentioned - jobs-first Brexit, mention the issues of young people and austerity, there's many other things."
Shadow chancellor John McDonnell said he believes there is a majority in Parliament to maintain the winter fuel allowance and triple lock pension, two things the Conservatives proposed changing in their manifesto.
"What we'll do is try to extract some of the main elements of our manifesto and present that as an amendment to the Queen's speech."
He continued: "On winter fuel allowance, for example, we think there's a majority in Parliament, even within the Conservative Party there are quite few Conservative MPs who'll say this is unacceptable, triple lock - exactly the same - the bedroom tax, I believe the DUP are in favour of scrapping the bedroom tax.
"There's a whole range of issues like that where we think there'll be a majority in Parliament."
Mr McDonnell said Labour should "draw on upon all the talents" when it considers its new frontbench although he also gave praise to the existing shadow cabinet.
He said: "Our shadow cabinet at the moment was a winning team. It's just won, effectively, votes that no one predicted we would so I don't want to break up that winning team."
Mr McDonnell said Mr Corbyn would decide the shadow cabinet positions, reiterating "It's a winning team I think we should hold together", adding there are also other positions to be filled.