European Commission President Ursula von der Leyen has urged the United Kingdom to "make up its mind" and consider the trade-offs it is willing to make in a post-Brexit deal.

Speaking to reporters in Brussels, von der Leyen acknowledged there were differences between the two sides following the first round of negotiations last week. She said the closer the UK's access to the single market－which it is leaving－the more it must adhere to European Union rules.

"We are aware that there are differences in the approach towards what scope should the future agreement have and what are－if I may say so－the rules of the game everybody has to abide to," she said.

"So it will be important that the UK makes up its mind－the closer they want to have access to the single market, the more they have to play by the rules that are the rules of the single market.

"If this is not the UK's choice then of course they will be more distant and it will be more difficult for the UK to access the single market."

She said it was "up to the UK within the negotiations to think about the trade-offs they want to take into account".

In response, the UK said it will propose its own free trade pact with the EU at next week's second round of negotiations on post-Brexit relations.

In a statement issued on Monday, Cabinet Office minister, Michael Gove, said UK negotiators would table a number of legal texts, including a draft free trade agreement, ahead of the talks.

The UK has set out its aim for a free trade agreement similar to the one the EU has with Canada, but Brussels has called for a closer relationship including a "level playing field" for areas including workers' rights, environmental protections and state subsidies to ensure fair competition between neighboring economies.

The next negotiating round will take place from March 18-20 in London.

Gove said the first round of talks in Brussels had "in some areas identified a degree of common understanding of the ground that future talks could cover".

"In other areas, notably fisheries, governance and dispute settlement, and the so-called 'level playing field', there were, as expected, significant differences," he added.

The UK government wants a new agreement on fisheries, based on methodology used for the EU-Norway fisheries deal. That, says UK officials, should allow UK vessels to be able to catch more fish.

The UK wants the fisheries sector to be separate from the broader UK-EU free trade agreement. Other areas include aviation, the civil nuclear industry, and police and judicial cooperation.