US stock futures have traded sideways in Asia as investors gave a cautious welcome to a deal being struck on a long-awaited US stimulus bill, though “difficult” Brexit talks drag on with no agreement in sight.

Sterling slipped 0.6 per cent to $US1.3436 after several European countries closed their borders to the UK as the country entered a tougher lockdown to fight a new strain of coronavirus.

Prime Minister Boris Johnson will chair an emergency response meeting on Monday to discuss international travel and the flow of freight in and out of Britain.

In the United States, Republican US Senate Majority Leader Mitch McConnell said an agreement had been reached by congressional leaders on a $US900 billion COVID-19 relief bill.

The news saw futures for the S&P 500 jump at first, only to fade back to flat as the morning progressed.

Nikkei futures were trading firmer at 26,885, after the cash index closed at 26,763 on Friday.

The US dollar index edged up a little to 90.147 and away from last week’s trough of 89.723 which had been the lowest since April 2018.

The euro likewise edged back to $US1.2230, while the dollar was a shade firmer on the yen at 103.36.

The pause in the dollar’s decline saw gold prices pare a little of their recent gains, dipping 0.3 per cent to $US1,880 an ounce .