* Pan-European FTSEurofirst 300 index falls 0.4 percent
* Athens ATG index down 2.9 percent on political uncertainty
* Multi-year lows for oil and copper hurt commodities stocks
By Atul Prakash and Lionel Laurent
LONDON, Jan 5 (Reuters) - Concerns over Greece's future in the euro zone and a sharp decline in commodities stocks triggered by lower crude oil and metals prices kept European equities under pressure on Monday.
The pan-European FTSEurofirst 300 index was down 0.4 percent at 1,357.71 points by 1137 GMT, with benchmark indexes in London, Frankfurt and Paris also falling 0.5 to 0.8 percent.
Energy and mining stocks fell the most, with the European oil and gas and the basic resources indexes falling 2.6 percent and 2.2 percent respectively after a supply glut sent oil prices to a 5-1/2-year low and copper hit a 4-1/2-year trough due to a stronger dollar.
With political uncertainty in Greece rattling markets before elections later this month, German Vice-Chancellor Sigmar Gabriel said the German government wanted Greece to stay in the euro zone.
The Jan. 25 election in Greece could vault the left-wing Syriza party into power, raising the risk of a sovereign default and severe losses for the European Central Bank on any Greek bonds it holds.
"If Greece is seen to be an issue which continues to contaminate the euro zone, maybe it's the time to think more seriously about reforming the euro zone," Peter Dixon, equity strategist at Commerzbank, said.
"But I think we will get a little bit less market volatility than we saw some years ago because the systemic risk that Greece poses to Europe is a lot smaller. For example, banks have significantly cut their risk exposure to Greece."
The Athens ATG index fell 3.9 percent, with lenders Bank of Piraeus and Alpha Bank down 5.1 percent and 5.7 percent respectively.
However, expectations that the European Central Bank might unveil some extra stimulus measures in a bid to boost the economy and quash fears of a deflationary spiral provided some support to the market.
Later in the day, German data is expected to show that inflation fell further in December. Data from five German states on Monday morning showed across-the-board declines, largely a result of falling energy prices.
The prospect of cheaper oil and a weaker euro helped travel and leisure stocks rise 1 percent.
Carnival, IAG and Air France-KLM rose 2.3 to 3.2 percent, while Ryanair shares, up 2.4 percent, hit an all-time high after the company said December traffic grew 20 percent.
Italian eye wear company Luxottica rose 2.6 percent, also hitting an all-time high, after La Stampa quoted the company as saying it would benefit from a weaker euro/dollar exchange rate in its fourth-quarter results. (Editing by Ruth Pitchford)