There is "room to manoeuvre" on the key issue of free movement when the UK leaves the European Union, Labour's shadow foreign secretary has insisted.
EU leaders have said free movement must be accepted if the UK is to retain full membership of the single market.
But Emily Thornberry said the UK had "common cause" with other countries and urged "good faith" in negotiations.
The government says it wants the maximum possible access to the single market and control of the UK's borders.
Labour says it wants guaranteed access to the single market, which removes tariffs and non-tariff barriers from trade within the EU, after Brexit.
On Saturday, shadow home secretary Diane Abbott told The Guardian such access would mean there could be "no deal to be done on freedom of movement".
But speaking on the BBC's Andrew Marr Show, Ms Thornberry said she believed there was "quite a lot of room to manoeuvre" on free movement.
She said "a whole range of options" could be looked at including changing the definition of a worker for free movement purposes.
People "would still be allowed to come here", she said, but for how long they were allowed to look for work or in which parts of the country could be reviewed.
"We have a common cause with other people across Europe in terms of exactly what free movement of workers means, and I think there's more work that could be done if it was done in an atmosphere of good faith," she said, accusing Foreign Secretary Boris Johnson of "undermining any good faith" with other EU countries.
Ms Thornberry also said too many people were coming to the UK, calling for action to tackle a "skills shortage" among UK workers. She declined to rule out a second referendum on the terms of the final Brexit deal.
Asked whether she agreed with Tony Blair and Sir John Major that a second referendum should not be ruled out, she said the Brexit process should be taken "in stages", adding that it was impossible to have a debate about how to leave the EU because of the lack of information provided by the government.
She urged ministers to "come out of their darkened room" and set out their negotiating strategy, adding: "Let us start with what it is the government wants to negotiate and then we can have a reaction from the public and a proper debate, and then we can decide how to proceed."
Also on Marr, former cabinet minister and Vote Leave campaign chief Michael Gove said the single market was a "bureaucratic web" which the UK should leave, as well as exiting the customs union.
He called for a "fair migration policy which does not discriminate between EU citizens and others".
Mr Gove also warned against attempts to over-complicate Brexit and suggested that transitional measures could be an attempt to keep the UK in the EU.