* Graphic: World FX rates in 2020 tmsnrt.rs/2RBWI5E By Kevin Buckland TOKYO, Dec 15 (Reuters) - The dollar traded near 2 1/2-year lows against major peers on Tuesday as demand for the safest assets flagged amid progress toward agreeing U.S. fiscal stimulus and optimism for a Brexit deal. The greenback was near its weakest since mid-2018 against the euro and UK pound with U.S. lawmakers scurrying to ready $1.4 trillion in spending. A $908 billion bipartisan COVID-19 relief plan will be split into two packages, a person briefed on the matter said, raising hopes that at least a large part of the plan that already has bipartisan support will be approved. "The big picture is that 2021 looks increasingly promising for global growth, and while the U.S. will certainly be a part of that, the global reflation trade is going to support the risk-sensitive currencies like the Australian dollar," said Westpac currency analyst Sean Callow. "The dollar is likely to be in the group of laggards, along with the likes of the yen." Across the Atlantic, European Union Brexit negotiator Michel Barnier said that sealing a trade pact with Britain was still possible, sowing hope that a deal can be reached with just days to avert a turbulent exit for the UK from the trade bloc at the end of the month. The British pound rose 0.1% against the dollar to $1.3332 , after jumping 0.8% on Monday. It reached a 2 1/2-year high of $1.3540 earlier this month. The greenback slipped 0.1% to $1.2150 per euro, trading near a 2 1/2-year low of $1.2177 touched again on Monday. COVID-19 vaccine roll-outs in the United States and Britain also buoyed risk sentiment, but optimism was tempered by spikes in infection and death rates. London will go into a tighter lockdown amid the discovery of a new variant of the virus. The dollar index was little changed at 90.705 after Monday sinking as low as 90.419, a level unseen since April 2018. The currency added 0.1% to 104.125 yen, another traditional safe-haven asset. "With the roll-out of vaccines starting in the U.S. and the UK, we expect shutdowns to reduce in frequency and intensity, allowing the USD to resume its downtrend," Commonwealth Bank of Australia currency analyst Joe Capurso wrote in a client note. An agreement on fiscal stimulus would also "undermine" the U.S. dollar, he wrote. The offshore Chinese yuan weakened 0.2% to 6.5444 per dollar. It reached 6.4975 earlier this month for the first time since June 2018. The onshore yuan traded at 6.5549. A Chinese official said Tuesday that the country could make targeted policy adjustments as the economy improves. The Aussie slipped 0.2% to 75.130 U.S. cents after touching the highest since June 2018 at 75.780 on Monday. The New Zealand dollar lost 0.1% to 70.72 U.S. cents after reaching 71.20 the previous session for the first time since April 2018. ======================================================== Currency bid prices at 12:58PM (358 GMT) Description RIC Last U.S. Close Pct Change YTD Pct High Bid Low Bid Previous Change Session Euro/Dollar $1.2153 $1.2143 +0.08% +8.40% +1.2163 +1.2144 Dollar/Yen 104.1150 104.0450 +0.02% -4.19% +104.1370 +104.0000 Euro/Yen 126.55 126.33 +0.17% +3.77% +126.5700 +126.3300 Dollar/Swiss 0.8866 0.8869 -0.02% -8.37% +0.8870 +0.8860 Sterling/Dollar 1.3336 1.3327 +0.06% +0.54% +1.3346 +1.3312 Dollar/Canadian 1.2766 1.2767 +0.02% -1.71% +1.2768 +1.2751 Aussie/Dollar 0.7515 0.7532 -0.21% +7.12% +0.7545 +0.7513 NZ 0.7076 0.7082 -0.10% +5.14% +0.7090 +0.7073 Dollar/Dollar All spots Tokyo spots Europe spots Volatilities Tokyo Forex market info from BOJ (Editing by Sam Holmes)